Rash ?? Help

Kristen
So I got this rash on my first period after going off birth control.  It went away quickly then came back on my last cycle before getting pregnant and hasn't really gone away.  It isn't itchy or raised and doesn't change with heat or anything but it's on my thigh under my breast and around my belly button.  My doctor said its probably just hormones but has anyone else had this did it go away??