acne
"I had been using products that contained benzoyl peroxide to control my acne.  When I heard that the FDA had approved adapalene for over-the-counter sales I said that I should give it a try - it used to be a prescription drug so it must be good.  WRONG!  I used Differin for over two weeks and all of the while my acne got continuously worse.  So, I went back to benzoyl peroxide."