I would reccomment switching brands of anti-biotic acne treatment. I was on minocycline for over a year, and it seemed to be working quite well at first. As time went on it became less effective. Eventually, my immune system did become weak, as you suspected. It ended up causing me to develope candita, which i am still stuggling to get rid of. The acne is worse than ever and my skin reacts to every little toxin in my body. If I eat ANY yeast or sugar, a zit or 5 is garunteed the next morning. Hope this answers your question. SWITCH!!!