I have rashes on my inner thigh that are red, circlular raised rings,and stops at the spot where my thigh and crotch intersect. I wear briefs but fill uncomfortable in any thing else,I don't sweet much but it could have been the cause,I am a virgin so it isn't sexually transmitted,and also it stated of really bad on 1 side and a few months later stated lightly on the other side. I applied a cream suggested by my doctor and that cured it however left large black marks and now it is happening again..how to get rid of the black marks as they look really ugly