body acne

I’ve gotten some really bad acne on my chest and shoulders, along with keratosis pilaris on my arms. This all happened shortly after I got my first period in December, so that may have something to do with it. I feel really self conscious about it, especially since I do track and field and have to wear a tiny uniform that shows it. I’ve been to the doctor and gotten some Tretinoin Cream, and i’m moisturizing the keratosis. I just need some tips on getting rid of my skin problems, thanks!!