since you had unprotected sex, you should cover your bases with full std testing. chlamydia, gonorrhea, syphilis, herpes , hiv and hepatitis testing can all be done now since so much time has passed.
It was not however I was stupid and eager, so far this rash is the only thing I have.
you need to be seen and get a proper exam done to find out what is going on. we'd just be guessing.
not likely this is std related. more likely it's a fungal infection but you'd need to be seen to find out for sure.
was your sex protected?
grace