Pimples in groin area

I currently have a few pimples that have appeared around my groin area. I do "shave/trim' and recently did that but a few other systems have me extra worried.

The past weekend I had unprotected sex with the girl i am seeing, and we were fairly active. The following day (about 24 hours after the last time we had sex) I became quite itchy in the groin area, but could not see anything there. I had also been driving for 5 hours straight so thought perhaps i was just sitting uncomfortable.

A couple days later I got a pimple down there, that I then popped and now I have quite a few. When I popped it, I only noticed blood, nothing else. I have already disclosed my concerns to the girl I am seeing and she admitted to being tested a month ago and I am her first partner after that. I have actually never been tested for an STD before, but have never had any symptoms like this before either. Also, I do play a lot of sports so sweating in that region isn't uncommon for me. The pimples don't hurt and the itchy has faded though I think my paranoia in my mind has me creating itches that aren't there...

Is this just acne or have I managed to pick up something?