<PAGE>   1

                                                                    EXHIBIT 10.8

                                  REVOLVER NOTE

$8,000,000.00                                                Birmingham, Alabama
                                                                    May 10, 2001

         FOR VALUE RECEIVED, PROASSURANCE CORPORATION, a Delaware corporation
(the "Borrower"), promises to pay to the order of BANK OF AMERICA, N.A., a
national banking association (the "Lender"), the principal sum of EIGHT MILLION
AND NO/100 DOLLARS ($8,000,000.00), or such lesser amount as shall equal the
aggregate unpaid principal amount of all Borrowings disbursed by the Lender to
the Borrower pursuant to Section 2.1 of the Credit Agreement referred to below,
on the dates and in the amounts provided for Borrowings under the Revolver
Facility pursuant to the Credit Agreement. The Borrower promises to pay interest
on the unpaid principal amount of this note on the dates and at the rate or
rates provided for in the Credit Agreement. Interest on any overdue principal of
and, to the extent permitted by law, overdue interest on the principal amount
hereof shall bear interest at the Default Rate, as provided for in the Credit
Agreement. All such payments of principal and interest shall be made in lawful
money of the United States in Federal or other immediately available funds at
the office of SouthTrust Bank, as Administrative Agent, 420 North 20th Street,
Birmingham, Alabama 35203, or such other address as may be specified from time
to time pursuant to the Credit Agreement.

         All Borrowings under the Revolver Facility funded by the Lender, the
respective maturities thereof, the interest rates from time to time applicable
thereto, and all repayments of the principal thereof shall be recorded by the
Lender and, prior to any transfer hereof, endorsed by the Lender on the schedule
attached hereto, or on a continuation of such schedule attached to and made a
part hereof; provided that the failure of the Lender to make any such
recordation or endorsement shall not affect the obligations of the Borrower
hereunder or under the Credit Agreement.

         This note is one of the Revolver Notes referred to in the Credit
Agreement dated as of May 10, 2001 among the Borrower, the Lenders listed on the
signature pages thereof, and SouthTrust Bank, as Lead Arranger, Syndication
Agent and Administrative Agent, and Bank of America, National Association, as
Co-Arranger (as the same may be amended and modified from time to time, the
"Credit Agreement"). Terms defined in the Credit Agreement are used herein with
the same meanings. Reference is made to the Credit Agreement for provisions for
the optional and mandatory prepayment and the repayment hereof and the
acceleration of the maturity hereof, as well as the obligation of the Borrower
to pay all costs of collection, including reasonable attorneys fees, in the
event this note is collected by law or through an attorney at law. This note is
entitled to the security provided by the Credit Agreement and the Collateral
Documents referred to therein.

         The Borrower hereby waives presentment, demand, notice of dishonor,
protest, notice of demand, protest and nonpayment and any other notice required
by law relative hereto, except to the extent as otherwise may be expressly
provided for in the Credit Agreement.

         THIS NOTE IS MADE AND DELIVERED IN THE STATE OF ALABAMA AND SHALL BE
CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF ALABAMA
WITHOUT REFERENCE TO THE CONFLICTS OR CHOICE OF LAW PRINCIPLES THEREOF.

        [Remainder of Page Intentionally Blank. Signature Page Follows.]


                                        1
<PAGE>   2

         IN WITNESS WHEREOF, the Borrower has caused this note to be duly
executed, under seal, by its duly authorized officer as of the day and year
first above written.

                                    PROASSURANCE CORPORATION


                                    By:
                                       -----------------------------------------
                                       Name: A. Derrill Crowe
                                       Title: Chairman

[CORPORATE SEAL]


                                        2
<PAGE>   3

                                                                      SCHEDULE A
                                                                TO REVOLVER NOTE

                         LOANS AND PAYMENTS OF PRINCIPAL

<TABLE>
<CAPTION>
     DATE           BASE RATE BORROWING             AMOUNT            AMOUNT OF           MATURITY            NOTATION
                     OR EURODOLLAR RATE          OF BORROWING         PRINCIPAL             DATE              MADE BY
                         BORROWING                                      REPAID
<S>                 <C>                          <C>                  <C>                 <C>                 <C>

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------

--------------     ------------------------      -----------------    --------------      ---------------     ---------------
</TABLE>


                                       3