The skin's final appearance is usually excellent. The medication is rubbed on the keratoses for three to six weeks. After one week the treated area starts to get raw. The applications are continued until your physician determines that you have the needed results. Healing starts when the 5-FU is stopped.
Sun damage is permanent.
Once sun damage has progressed to the point where actinic keratoses develop, new keratoses may appear even without further sun exposure. You should avoid excessive sun exposure but don't go overboard and deprive yourself of the pleasure of being outdoors. Reasonable sun protection should be your aim.