<PAGE>



                               SECOND AMENDMENT TO
                           INVESTORS' RIGHTS AGREEMENT


         THIS SECOND AMENDMENT TO INVESTORS' RIGHTS AGREEMENT (this "AMENDMENT")
is entered into as of January 10, 2001, by and among OMP, Inc., a Delaware
corporation (the "COMPANY") (successor to Obagi Medical Products, Inc. which was
formerly known as OMP Acquisition Corporation), Mandarin Partners LLC
("MANDARIN"), and the Zein and Samar Obagi Family Trust ("OBAGI") (collectively
referred to as the "PARTIES").

                                    RECITALS

         WHEREAS, the Parties entered into an Investors' Rights Agreement, dated
as of December 2, 1997, as amended as of November 15, 2000 (the "INVESTORS'
RIGHTS AGREEMENT"); and

         WHEREAS, Mandarin has made a distribution of the Company's capital
stock owned by it to its beneficial owners: Stonington Capital Appreciation 1994
Fund, L.P. ("STONINGTON"), Peter P. Tong, Tong Family Limited Partnership, Ian
G. Walker and Noel Urben (collectively, the "MANDARIN INVESTORS"); and

         WHEREAS, the Company, Mandarin and Obagi desire to amend the Investors'
Rights Agreement to eliminate all rights of Mandarin under the Investors' Rights
Agreement, release Mandarin from its obligations under the Investors' Rights
Agreement and allow each of the Mandarin Investors to join the Investors' Rights
Agreement as if it or he was an original party thereto.

         NOW, THEREFORE, in consideration of the mutual premises and promises
herein contained and other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties hereto agree as
follows:

                                    AGREEMENT

         1. TRANSFER OF MANDARIN'S INTEREST. Effective upon the execution and
delivery of this Amendment by the Parties and the Mandarin Investors, Mandarin
shall assign and transfer, and the Mandarin Investors agree to assume, all of
Mandarin's rights and obligations under the Investors' Rights Agreement. Without
limiting the generality of the foregoing, each of the members of the Mandarin
Investors shall be a "Holder" (as defined in the Investors' Rights Agreement)
and agrees to be bound by and subject to the terms and conditions of the
Investors' Rights Agreement, including, without limitation, the provisions of
Section 2.3 of the Investors' Rights Agreement. Effective upon the execution and
delivery of this Amendment by the Mandarin Investors, Mandarin shall be released
from all rights and obligations it has under the Investors' Rights Agreement.

<PAGE>


         2. AMENDMENTS TO THE INVESTORS' RIGHTS AGREEMENT.


         (a) DEFINITIONS. Section 1 of the Investors' Rights Agreement is hereby
amended by adding the following definitions in the appropriate alphabetical
order:

                  "The term "Co-Sale Investors" shall mean, collectively, Obagi
         and each of the Mandarin Individual Investors.

                  The term "Mandarin Investors" shall mean, collectively,
         Stonington, Peter P. Tong, Tong Family Limited Partnership, Ian G.
         Walker and Noel Urben.

                  The term "Mandarin Individual Investors" shall mean,
         collectively, Peter P. Tong, Tong Family Limited Partnership, Ian G.
         Walker and Noel Urben.

                  The term "Stonington" shall mean Stonington Capital
         Appreciation 1994 Fund, L.P."

         (b) CO-SALE RIGHTS. Section 4 of the Investors' Rights Agreement is
hereby amended by deleting such Section in its entirety and replacing it with
the following:

                  "4. CO-SALE RIGHTS.

                  4.1 SALES BY STONINGTON.

                  (a) If Stonington proposes to sell or transfer any shares of
         Co-Sale Stock in one or more related transactions, then Stonington
         shall promptly give written notice (the "Notice") to the Company and
         each of the Co-Sale Investors at least twenty (20) days prior to the
         closing of such sale or transfer. The Notice shall describe in
         reasonable detail the proposed sale or transfer including, without
         limitation, the class, series and number of shares of Co-Sale Stock to
         be sold or transferred, the nature of such sale or transfer, the
         consideration to be paid, and the name and address of each prospective
         purchaser or transferee. In the event that the sale or transfer is
         being made pursuant to the provisions or Sections 4.1 or 4.2 hereof,
         the Notice shall state under which section of this Agreement the sale
         or transfer is being made.

                  (b) Each of the Co-Sale Investors shall have the right,
         exercisable upon written notice to Stonington within fifteen (15) days
         after receipt of the Notice, to participate in such sale of Co-Sale
         Stock on the same terms and conditions; provided, that such Co-Sale
         Investor owns shares of the same class or classes as the Co-Sale Stock
         identified in the Notice.

                  (c) Each of the Co-Sale Investors may sell all or any part of
         that number of shares of Co-Sale Stock, of the same class and/or series
         as that identified in the Notice, equal to the product obtained by
         multiplying (i) the aggregate number of shares of Co-Sale Stock covered
         by the Notice by (ii) a fraction the numerator of which is the number


                                      -2-
<PAGE>


         of shares of Co-Sale Stock of the same class and/or series identified
         in the Notice owned by such Co-Sale Investor at the time of the sale or
         transfer and the denominator of which is the total number of shares of
         Co-Sale Stock of the same class and/or series identified in the Notice
         owned by Stonington and all Co-Sale Investors at the time of the sale
         or transfer.

                  (d) Each of the Co-Sale Investors shall effect its
         participation in the sale by promptly delivering to Stonington for
         transfer to the prospective purchaser one or more certificates,
         properly endorsed for transfer, which represent the type and number of
         shares of Co-Sale Stock which such Co-Sale Investor elects to sell.

                  (e) The stock certificate or certificates that any Co-Sale
         Investor delivers to Stonington pursuant to Section 4.1(d) shall be
         transferred to the prospective purchaser in consummation of the sale of
         the Co-Sale Stock pursuant to the terms and conditions specified in the
         Notice, and Stonington shall concurrently therewith remit to such
         Co-Sale Investor that portion of the sale proceeds to which such
         Co-Sale Investor is entitled by reason of its participation in such
         sale. To the extent that any prospective purchaser or purchasers
         prohibits such assignment or otherwise refuses to purchase shares or
         other securities from any Co-Sale Investor, Stonington shall not sell
         to such prospective purchaser or purchasers any Co-Sale Stock unless
         and until, simultaneously with such sale, Stonington shall purchase
         such shares from such Co-Sale Investor for the same consideration and
         on the same terms and conditions as the proposed transfer described in
         the Notice.

                  (f) The exercise or non-exercise of the rights of each Co-Sale
         Investor to participate in one or more sales of Co-Sale Stock made by
         Stonington shall not adversely affect any Co-Sale Investor's rights to
         participate in subsequent sales of Co-Sale Stock subject to Section
         4.1(a).

                  (g) If any of the Co-Sale Investors does not elect to
         participate in the sale of the Co-Sale Stock subject to the Notice,
         Stonington may, not later than ninety (90) days following delivery to
         the Company and the Co-Sale Investors of the Notice, conclude a
         transfer of not less than all of the Co-Sale Stock covered by the
         Notice on terms and conditions not more favorable to the transferor
         than those described in the Notice. Any proposed transfer on terms and
         conditions more favorable than those described in the Notice, as well
         as any subsequent proposed transfer of any of the Co-Sale Stock by
         Stonington, shall again be subject to the co-sale rights of each of the
         Co-Sale Investors and shall require compliance by Stonington with the
         procedures described in this Section 4.1.

                  4.2 EXEMPT TRANSFERS.

                  (a) Notwithstanding the foregoing, the co-sale rights of the
         Co-Sale Investors shall not apply to (i) any pledge of Co-Sale Stock
         made pursuant to a bona fide loan transaction that creates a mere
         security interest, (ii) any bona fide gift or charitable


                                      -3-
<PAGE>

         donation or (iii) any distribution to the partners of Stonington;
         provided that Stonington shall inform each of the Co-Sale Investors of
         such pledge, transfer, gift, donation or distribution prior to
         effecting it.

                  (b) Notwithstanding the foregoing, the provisions of Section 4
         shall not apply to the sale of any Co-Sale Stock (i) to the public
         pursuant to a registration statement filed with, and declared effective
         by, the Securities and Exchange Commission under the Act or (ii) to the
         Company."

         (c) RESTRICTIONS ON TRANSFER. Section 6 of the Investors' Rights
Agreement is hereby amended by deleting such Section in its entirety and
replacing it with the following:

                  "6. RESTRICTIONS ON TRANSFER.

                  6.1 Obagi shall be prohibited from selling or otherwise
         transferring any shares of Registrable Securities or Co-Sale Stock
         issued or issuable to it or from selling or otherwise transferring any
         right to acquire such securities to any party other than the Mandarin
         Investors at any time prior to the earlier of (i) the closing of a firm
         commitment underwritten public offering pursuant to an effective
         registration statement under the Act covering the offer and sale of the
         Company's Common Stock at an aggregate offering price of not less than
         $7,500,000, (ii) the closing of the Company's sale of all or
         substantially all of its assets or the acquisition of the Company by
         another entity by means of merger or consolidation resulting in the
         exchange of the outstanding shares of the Company's capital stock for
         securities or consideration issued, or caused to be issued, by the
         acquiring entity or its subsidiary or (iii) the tenth anniversary of
         the date of this Agreement (provided that in the case of clause (iii)
         hereof, after such tenth anniversary Obagi may sell or otherwise
         transfer such Registered Securities or Co-Sale Stock only in compliance
         with Section 6.2 below).

                  6.2 If an event specified in clause (i) or (ii) of Section 6.1
         shall have not yet occurred as of the tenth anniversary of the date of
         this Agreement and Obagi desires to sell or otherwise transfer any such
         Registrable Securities or Co-Sale Stock (the "Target Stock") at any
         time after such tenth anniversary, then Obagi shall promptly deliver to
         the Company and each of the Mandarin Investors written notice of the
         intended disposition and the terms and conditions thereof, including
         the identity of any proposed purchaser and the price per share of the
         securities to be so disposed (the "Offer Notice"). Thereafter, the
         Company and the Mandarin Investors or any of them may elect to purchase
         any or all of the Target Stock on the terms and conditions set forth in
         the Offer Notice, such purchase to occur within twenty (20) business
         days after receipt by the Company and the Mandarin Investors of the
         Offer Notice (the "Wait Period"). The Company and the Mandarin
         Investors shall each negotiate in good faith in determining any
         allocation between them of the Target Stock offered in the Offer
         Notice. If the Company and the Mandarin Investors or any of them have
         not purchased all such Target Stock prior to expiration of the Wait
         Period, the Company's and the Mandarin Investors' right to purchase any
         Target Stock not so purchased by them shall lapse, expire and be of no


                                      -4-
<PAGE>


         further effect. Any Target Stock not purchased by the Company or by the
         Mandarin Investors which is thereafter transferred by Obagi to a third
         party shall be subject to the provisions of Sections 5 and 6, and 16
         such transferee shall, as a condition precedent to such transfer, agree
         to be bound by the provisions of Sections 5 and 6 and shall be treated
         as "Obagi" for the purposes of Sections 5 and 6."

         3. EFFECT OF AMENDMENT. All terms and provisions of the Investors'
Rights Agreement shall continue in full force and effect except as expressly
modified in this Amendment. Each reference in the Investors' Rights Agreement to
"this Agreement," "hereunder," "hereof," or words of like import, and each
reference to the Investors' Rights Agreement in any and all instruments or
documents provided for in the Investors' Rights Agreement or delivered or to be
delivered thereunder or in connection therewith, shall, except where the context
otherwise requires, be deemed a reference to the Investors' Rights Agreement as
amended hereby.

         4. NO THIRD-PARTY BENEFICIARIES. Nothing expressed or implied in this
Amendment is intended to confer upon any person, other than the parties hereto,
or their respective successors or permitted assigns, any rights, remedies,
obligations or liabilities under or by reason of this Amendment.

         5. COUNTERPARTS. This Amendment may be executed in counterparts, each
of which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

         6. CHOICE OF LAW; HEADINGS. This Amendment shall be governed by and
construed in accordance with the internal laws of the State of California
(regardless of such state's conflict of laws principles), and without reference
to any rules of construction regarding the party responsible for the drafting
hereof. Headings in this Amendment are for the purposes of reference only and
shall not limit or otherwise affect any of the terms hereof.

         7. SUCCESSORS AND ASSIGNS. This Amendment shall be binding upon and
inure to the benefit of the parties hereto and their respective successors and
permitted assigns.



                            [Signature Pages Follow]



                                      -5-
<PAGE>



         IN WITNESS WHEREOF, the parties have executed this Amendment on the day
and year first above written.


                                       OBAGI MEDICAL PRODUCTS, INC.


                                       By:
                                           --------------------------
                                           Phillip J. Rose, President


                                       SHAREHOLDERS:

                                       MANDARIN PARTNERS LLC


                                       By: /s/ Peter P. Tong
                                           --------------------------
                                           Peter P. Tong, Manager


                                       ZEIN AND SAMAR OBAGI FAMILY TRUST


                                       By: /s/ Zein Obagi
                                           --------------------------
                                           Dr. Zein Obagi, Trustee





                                      -6-
<PAGE>




                                     NEW SHAREHOLDERS:

                                     Stonington Capital Appreciation
                                     1994 Fund, L.P.

                                     By:  Stonington Partners, L.P., its general
                                          partner
                                          By:  Stonington Partners, Inc.,
                                               its general partner

                                     By:
                                        ----------------------------------------
                                     Name:
                                          --------------------------------------
                                     Title:
                                           -------------------------------------
                                     767 Fifth Avenue
                                     New York, New York 10153


                                     /s/ Peter P. Tong
                                     -------------------------------------------
                                     Peter P. Tong
                                     685 Spring Street
                                     PMB 210
                                     Friday Harbor, Washington 98250


                                     Tong Family Limited Partnership


                                     By: /s/ Peter P. Tong
                                     -------------------------------------------
                                              Peter P. Tong, Trustee
                                              685 Spring Street
                                              PMB 210
                                              Friday Harbor, Washington 98250


                                     /s/ Ian G. Walker
                                     -------------------------------------------
                                     Ian G. Walker
                                     c/o 310 Golden Shore
                                     Long Beach, California 90802


                                     /s/ Noel Urben
                                     -------------------------------------------
                                     Noel Urben
                                     86 Doubling Road
                                     Greenwich, CT  06830



                                      -7-