Although you do not ask about creams marketed for breast enlargement, I have received many letters in the past about them. I can see even less possibility that a cream would work than I can imagine a pill would. Although drugs can be absorbed through the skin, they then act by entering the blood stream and being carried to the tissues that they effect. They do not have any local effect on tissues deeper than the skin. Estrogen patches, for example, provide estrogen, which is absorbed through the skin into the blood stream where it is carried to all the organs of the body.
Some drugs work better when absorbed through the skin than when taken as pills.
Testosterone is a case in point, but here the patches work better than pills because the hormone is destroyed by the liver, and when taken as a pill, always passes through the liver first. I'm afraid I cannot offer any encouragement that the pill you mention will actually result in breast enlargement. If you are determined to have larger breasts, then surgical enlargement is the only solution. Silicone implants, which used to be the preferred way of doing it, were withdrawn from the market several years ago because of concerns that leakage could lead to autoimmune diseases such as lupus. Careful studies in the past couple of years have debunked that association, and most doctors who are not involved as plaintiff's witnesses in the thousands of suits that were brought because of this no longer accept that the association is real.