15 days ago, I received and gave oral sex on a woman. She also rubbed my penis on her vagina for a few minutes and there may have been 5 seconds of penetration (no condom). About 3 days ago, the tip of my penis started to feel irritated with a slight redness extending out of the pee hole just a bit down the shaft on the backside of the penis. It is still irritated. No discharge. A very, very minor burn (I'm hesitant to say "burn". It is a 1.5 on a 1-10 burn scale) when I pee. But mainly it feels irritated when I'm just sitting down and not peeing. Today, my thighs feel like they are almost slightly burning a bit (especially on the back side) but I don't see a rash.
2 days ago (13 days after the incident), I did a 8 panel STD test. Everything came back negative today.
I am very concerned about herpes (I know two weeks post incident may be too soon for the test. So I don't trust that it was negative). Someone else mentioned urethritis maybe.
HELP.