I was wearing a new thong I just bought(didn't wash it before wearing) while on my period last week and a slightly painful feeling behind my vagina closer to the anus started happening. Yesterday I had sex with this guy I kinda knew and we didn't end up using a condom, and I don't know his history. Today the painful spot was bugging me again so I looked with a mirror and now I have a sore in the spot, it is painful and I dont know what it is, could it be herpes? Its been barely 24 hours since I had sex with the guy.. can herpes show that soon or is it just a sore in general?