I Have A Rash Inside My Buttock Crack And It

I have a rash inside my buttock crack and it has itched a few times and when its warm outside my cracks between my legs and my buttock sweat and then the rash sometimes itches and I never noticed it before but when I am in the shower I rinse out by buttock crack and the cracks between my legs and my buttock and it feels better but the rash is still there when I was itching my family member looked in my butt and saw the rash