How To Get Rid Of Spots On My Butt Cheeks?

I have spots on my butt cheeks. Can you tell me what it is and what could be causing them. I have been getting spots all over me for about 6 months now. I went to a doctor before and she couldn't tell me what it was, so she just prescribed some antibiotics and this helped clear them up. A couple of weeks later, one or two started appearing again and as soon as they went another one or two would appear in a different place, now they are appearing on my butt cheeks the whole time, and it is very uncomfortable. What can I do to get rid of them for good, I don't want to be taking antibiotics the whole time.