What Causes Redness And Soreness On The Underside Of The Vagina?

I have an issue of redness and soreness on the bottom side of the penis by the "head." There was some dryness and "dandruff..." and though I used cortisone and that stopped, it is still red and sore. My ex has oral herpes, and only gave oral sex once - while not having an outbreak. A condom also broke once, but as far as I know, she had and has no sign of herpes. If I stretch the skin in one part, it could look like a blister... though not something you could pop or anything, and it might be my paranoia making something virtually unnoticeable seem sort of like a blister. I was thinking maybe jock itch? I'm not sure... I don't know what to try, and would like to know the likelihood as to whether or not it is herpes.