Mt dermatologist had me using Flourouracil on my forehead and chest once a day. When I went for my one month check-up on April 12th he told me to use it two times a day on both my forehead and chest. He said I'm supposed to break out in red rash before area on my forehead is cleared up. My condition is very mild, so far. What does this product do for the pre-cancer on my forehead and the white, scaly, non-cancerous tumors? What, if anything, does flourouracil do for dark sun spots?