Tretinoin is used to treat acne or other skin diseases as determined by your doctor. It works partly by keeping skin pores clear. One of the tretinoin creams is used to treat fine wrinkles, dark spots, or rough skin on the face caused by the damaging rays of the sun. It works by lightening the skin, replacing older skin with newer skin, and slowing down the way the body removes skin cells that may have been harmed by the sun. Tretinoin works best when used within a skin care program that includes protecting the treated skin from the sun. However, it does not completely or permanently erase these skin problems or greatly improve more obvious changes in the skin, such as deep wrinkles caused by the sun or the natural aging process.