About 3 months back I had unprotected sex with a female, a month later I started feeling this high heat sensation in my penis and follow that I started to have a hot sunburn type feeling in my thighs, which seemed to spread and get worse. I was tested for chlamydia, syphilis, gonorrhea, and HIV, all of which came back negative. After about a month and a half I went back to the doctor and was prescribed some anti-fungal cream, told to apply it twice a day to the affected area for at least 10 days. I used it for the 10 days and by day 18 the hot burning sensation had disappeared. Still I'm left with overly sensitive itchy skin, it feels like pins are stabbing into the afflicted area when I start to sweat, which goes all the way down to my knees and seems to be spreading into my lower legs. I also seem to be getting mildly sore (when touched) red bumps on areas where the skin is already bothered when it's irritated further (through clothing being rubbed on it) which disappear within 4 or 5 days. I've gotten this on my waist near my right hip, on the inner right thigh, and in various areas around my butt. I've never had anything like this before I slept with this girl, and at first I was incredibly worried when the first symptoms started showing up.
So what exactly is going on here? Do I have an STD? It was suggested to me that it might be scabies. The sunburn-like sensation disappearing after using the antifungal cream would suggest that it was indeed a fungal infection. But the skin is still terribly itchy and sensitive, even the feeling of my penis touching against my underwear feels like it's being poked with pins. Sitting down is just as bad, as is walking. It's bearable, but quite uncomfortable. Also it seems to feel much better when i'm out in the cold, it also decreases the uncomfortable feel for a fair bit of time after.