I have used fluorourcil several times. The last time was several months ago. I used it around my mouth, chin and just under the chin. I had a massive reaction that still has not completely healed. Also on my lower lip which has peeled chronically for years. I had large, angry sores with very thick scabs every place I applied it. I may have made it worse by trying many things that I hoped would speed the healing. Tea tree oil, various essential oils, calamine lotion, hydrogen peroxide, aloe Vera cream, hydrocortisone, Aquaphor, bacitrin, vitamin C serum and maybe others that I have forgotten. My doctor told me to never use it again. I had him take two biopsies in the worst areas to be sure it wasn’t skin cancer. It was hard not to pick at the scabs but it is finally healing.