Red Pelvic Rash After Sex

I recently (2 nights ago) had unprotected sex with a girl.  Immediately after sex, I noticed that I had developed a red rash that consisted of many red bumps.  The bumps were not raised, but they were everywhere.  There were not, and still are not, any red bumps on my actual genitals (penis or testicles); rather, they are all over my pelvic and pubic area over my penis and extend up to just shy of my belly-button.  I have no STDs to my knowledge but have never been tested. Furthermore, I have not talked with the girl about this yet.  Today, the individual bumps have gotten slightly larger (seems like inflamed).  I did exercise yesterday and today.  They are still not raised.  There is not much "burning" however the rash does itch quite a bit.  I am wondering what could be causing this, and how to get rid of it.  Here are some of the things I have been curious as to a cause. 1) simple irritation due to body friction during sex (she was on top and had some "stubbly" pubic hair from where she had obviously recently shaved maybe a day or two prior). 2) irritation due to not cleaning off my skin after we finished sex (I simply but my boxers back on and went to bed, leaving any bodily fluids to absorb in my skin). 3) a combination of 1 and 2. and finally 4) [saving worst for last] an STD.  I have read that herpes takes 2-3 days to show up, which makes me feel better about the situation.  Also, some of the symptoms listed with herpes do not match up with this (ie. intense burning and sore and causing nausea).  I have been applying lotion in efforts to reduce the rash, but that doesn't seem to be helping me too much.  I will say that this rash does seem comparable to a razor burn rash that I developed once in my life after shaving my pubic hair with a razor blade.  Please provide me with any and every form of feedback that you can.  Thank you for your time.

[Mikel5394]

I am also curious about this "rash". this exact thing has recently happened to me, and I'm not sure what to do, or what it is.  did you ever find out an answer to this condition...?