A-Ret Gel topical (for the skin) is used to treat acne, to smooth rough facial skin, and to reduce the appearance of fine wrinkles and mottled skin discoloration. Tretinoin is a form of vitamin A that helps the skin renew itself. Avoid getting A-Ret Gel medication in your eyes, mouth, vagina, or in the creases of your nose. You should not use tretinoin topical if you are allergic to it.