Back clear for everything , i have no itching at all , i know its not thrush or bv , what could it be?

Umm, hard to say.: Rashes are most difficult to diagnose without actually examining them. How long have you had the problem? Perhaps it would be wise to have your physician examine this in person. Then specific treatment and preventive measures could be discussed with more accuracy. Accurate information with a proper diagnosis can be a blessing in itself! don't torture yourself any longer--get help.