Skin Irritation On Penis after Wearing Condom

Saturday night, I had sex with my girlfriend. I used a normal Trojan Ultra-Lubricated condom. Both of us have only had sex with each other and have had sex many other times with no problem which hopefully rules out even the chance of an STD. But anyway, I developed several small red bumps almost in a ring around my penis right around where the condom would have ended. Like the rim of it. We had sex multiple times that night and for a while each time which leads me to believe that the condom could have irritated my skin. This morning, I woke up and it has gotten slightly worse. The bumps haven't spread at all but almost look like whitehead pimples, with a tiny bit of pus in the middle. Also, they have become somewhat itchy. I've done some research and for similar cases, people have suggested the idea of being allergic to the lubricant of the condom or a staph infection of some sort brought on by pubic hair follicles being irritated. Any ideas?

Thanks