ichy spot between the legs help my figure what it is?

[Midnight]

i have a small round spot on the inside of my leg that has just started itching constantly i am not a virgin but ive only had sex with one girl who has had very limited sex herself so im fairly certian its not an STD its about as big around as a dim meybe a bit smaller but large enough to probably not be a bugbite (why i would have been bitten there im not sure but i was just camping so i wolnt rule it out) its probably just a heat rash but if anyone has any other ideas i would be glad to hear them