I'm sure this question gets asked a dozen times a day, but I'm hoping you can help me out here.
About 4 1/2 months ago I had unprotected sex with a random girl I met at a random bar. Thing is, I was in a commited relationship (please don't judge). Being scared of the reprocussions, I talked a doctor into perscribing anti-biotics to treat the usual bacteria STDs. Since then I've been tested for HIV (17 weeks after), Syphilis (only 4 weeks after exposure), chlamydia and Gonorrhea (4 weeks after exposure), and a non-type-specific IgG test for HSV (17 weeks post exposure). Everything came back negative, but that hasn't stopped me from being paniced every time something new appears.
2 weeks ago, I noticed a couple small red spots on my glans, but had sex 2 days ago with my commited partner. Figuring it was just a yeast infection, I self treated for 5 days with Bactine and Lotriderm, and sure enough it went away. My partner self treated with a yeast infection kit and it went away for her.
Today, I found one single red spot under my forskin, below the glans, about 5 - 10 cm below the glans and maybe 3 cm across. It's noticably red, but doesn't hurt or itch. I have self-abused with a lot of masterbation lately, but the sore isn't in an area where I'd normally chafe, and it's nearly circular and feels raised. Looking at it under a magnifying glass, it seems to be that the skin is torn (or blistered) from the edges up and glistens like it's raw or if blistered, filled with water. I really can't tell if it's blistered or rubbed raw.
I will probably get it checked since I'm a basket case every time something unexpected happens on my penis, but I feel bad going back yet again (after going again and again and again over 4 months). Having said that, what does it sound like to you? Could it be the yeast infection flaring up again if 4 days didn't kill it entirely, or could it be chaffing I didn't notice before, or could it be a late to present itself STD given all the tests I've taken that have shown negative? Before you ask (and yes, I know what your going to say to this), but I'm 100% sure my partner has not cheated on me or infected me with anything.
Thanks for your replies.