red pimples in groin area

I had sex with a new woman last saturday night. I did not see anything unusaul around her vagina and she was confident she didn't have anything. I had a full spectrum of std tests done last month, just because and everything was negative.
The next night, sunday I had about 10-12 red pimples in in my groin area. Most are in the pubic hair area with a few just above it and a couple at or on the base of my shaft. They did not itch or hurt unless I rubbed or touched them. The bumps are small, about 2mm surrounded by red skin. She was shaven although she had stubble, and thought the vigorous grinding irritated my skin or else I was having an alergic (allergic) reaction to the motion lotion we used.  
My concerns are foculitus, genital warts, herpes or molluscum. I am very concerned about contracting a permanent std that I can spread.
It has now been a week and the redness had faded on most to a light pink. I also developed what appear to be canker sores that appeared sunday night as well. They are two white ovals inside the mouth. They appear to be going away as well, but  i thought they weren't contagious? She still has no visible signs of anything. Do I need to be concerned about any of the above or is there some other condition I should have checked out?

[Alan Rockoff, MD]

Your description most closely matches folliculitis.  This might well follow rubbing and lotion use.  Herpes causes blisters which scab, not pimples that stay and fade.  Warts and molluscum don't generally pop up that quickly.

If you continue to leave the spots alone and they fade away in another week or two, that would confirm the folliculitis diagnosis.  If they don't, see a doctor for a check.

You don't mention condom use.  That would not prevent folliculitis, but might well allay your concerns about ctaching the other things.

Best.

Dr. Rockoff

[angelina123]

A related discussion, red pimples on goin was started.