Hello. I had unprotected sex with my new girlfriend 7 weeks ago for the first time. Hours later I notice a few red dots on my penis head. They slowly faded away a week later, but then came back next time we had sex and there were a few more red dots that appeared. I thought maybe it was just from friction or something so didn't think much of it. But now this last time we had sex, which was about 3 weeks ago, the red dots sort of went away and now it more like a red rash. Just on the top side of my penis head. Been tested for all stds and other infections and everything was negative. I was also treated for yeast infection which did nothing. What could this be?? No doctors have had any clue. Please help.