Welcome to the STD forum.
While I understand your anxiety, apparently enhanced by your first sexual experience with another man (about which you seem emotionally conflicted, given your comments about counseling), I do not believe you caught any STD or any other infection from the sexual encounter. Most likely the doctor who treated you for common bacterial STDs did so as a precaution, not because s/he believed you actually were infected. The drugs you received are 100% effective in preventing or eradicating chlamydia, gonorrhea, syphilis, and nongonococcal urethritis (NGU) -- i.e., just about all the treatable STDs -- so if by chance you were infected despite lack of significant risk, those STDs are not an issue now.
Oral sex is basically safe sex. Not completely free of STD/HIV transmission risk, but much less risky than unprotected anal or vaginal sex. Frottage -- the fancy term for body rubbing without penetration -- is risk free for HIV and all the infections mentioned above. There might be slight risk for HPV and herpes, however.
Which brings us to the main concern, whether your penile lesion plus other symptoms were due to herpes. That certainly is a possibility. As suggested above, the nature of the exposure makes herpes unlikely; but on the other hand, some of your symptoms are a pretty good story for herpes. The genital pimple-like lesion is an obvious one. However, initial herpes usually causes several penile lesions, not just one. An inflamed lymph node in the groin also fits with herpes. However, these problems also fit with various non-STD problems, like a staph or strep infection of the penile skin. Diarrhea does not fit for herpes or any other STD. The systemic symptoms -- fever, etc -- could go along with just about anything. The fact that your doctor didn't see anything seriously wrong when you returned for the second visit should be reassuring. Presumably you didn't show him the penile lesion, or perhaps it had healed. If he were aware of it, most likely he would have tested the lesion for HSV.
All things considered, I think herpes is a possibility but not a probability. You might have caught a garden variety virus of some sort from your partner. Aside from herpes, no other STD (including HIV) is a realistic possibility.
What to do now? Talk to your provider about herpes and testing for it. If he agrees it is a possibility, you could have a blood test now and again in 3 months, to see if a negative test for either herpes type (HSV-1 or HSV-2) becomes positive later. Or if a genital pimple/sore reappears, see your doc immediately (within 1-2 days) for an HSV test from the lesion.
I hope this helps. Best wishes-- HHH, MD
Self assessment of enlarged lymph nodes is notoriously unreliable. If you think you have it, see a provider. There is no possible connection between prostatitis, inguinal lymph node enlargement, and kidney stones.
You need to stop over-thinking your sexual exposure. Don't assume every little symptom you might experience is somehow related to that event.
That will be all for this thread. Take care.
Thank you for your advice, this does give me a little relief. Although, I just noticed that the lymph on my left side groin has started to swell with occasional pain. I didn't mention in my origianl post, I have had kidney stones in the past. Could this be a factor with the lymph swelling or could I possibly have prostasis?
I forgot to add, there was no anal penetration during the encounter.