M.S.
Sounds very similar to my daughter who got acne at about the same age. She takes Zantac for acid reflux as well. I ended up taking her to the doc because the acne seemed out of control to me as it spread from her face to her shoulders, back, arms and chest. He said that really was all it was and to leave it alone cause anything you put on it might clear it up temporarily, but could have it coming back even more. He told me to cut out peanut butter entirely and cut back on dairy, but not to cut out dairy altogether. I did cut the peanut butter and cutback on dairy and it cleared up within a few days and her skin has been clear ever since.