What do you mean by "lighting up"?
My Flouruoracil treatment is brand name "Carac" and I posted a lengthy comment entitled "Carac side effects" before I read your post. I should probably start commenting under Efudex, since there seem to be more contibutors using that brand product. I am about half way through my once per day for 4-6 weeks treatment for AK.
Is some kind of a peel also effective in preventing cancers, or are they primarily for appearance? barngirl (60 yrs old so hardly a "girl", but I do spend time in the barn. Maybe should be called oldbarnhag. :-) )