hi there, I've been having these outbreaks of red spots on my butt cheeks for a while now they appear 3 or 4 at once, some are just red and some with like a white fat thing on it like a blister or something. they will last 3 to 4 days and when they disappear it leaves black marks and they really affected my life as I am a fair complexion. Now they start to appear on my upper leg which I'm depressed about cause people can see if I wear a short. I went to my doctor she gave a cream for it but nothing works and I realised that they comes once a month please help me to stop it thanks.