Two years ago I had unprotected sex, the day after I was sore and then a few days after one small sore on the skin below vaginal opening and anus appeared(perineum i think it is called). I got a blood test for herpes which i found out i did not have it and i was tested for all other STD which came back negative. I have an anal fissure and sometimes if i wipe too hard the fissure will rip but also the skin in between my vagina and anus will become sore and about two days later a sore like a blister will appear similar to the sore I got the day after having unprotected sex. I had sex with a condom and the following day the skin below vaginal opening became sore if i wipe and then a sore would appear. This soreness seemed to happen after I was placed on birth control (depo shot) i had sex twice before being on the shot and never had this problem after sex. What could this be?