I had a new encounter with a person I do not know well and although she said she was STI free, I cannot be sure. This encounter was non-penetrative but included me fingering her and a lot of grinding/dry humping. She was completely naked and I only had my boxers on. At one point she started to masturbate me through my boxers and also rubbed my covered penis on her bare vagina. I don't believe my penis was exposed through the boxers but I cannot be certain as I wasn't looking down there. If my bare penis did touch her bare vagina it would have been pretty brief but I do believe my boxers were covering for protection. Either way my boxers likely had vaginal fluid on them and my hands as well, but I didn't touch my penis before washing my hands. However her fluid likely got on my thighs/legs.  The next day I woke up with a big red spot on my inner thigh, so I am concerned. It's not a cluster or anything and may be a pimple I'm not sure. Also I am having testicle pain and sensations too. Do you think it's possible I could have gotten a STI from this? I didn't think so but reading on sites like Planned Parenthood it says its possible. I'm planning to get this spot tested for HSV but what other tests do you recommend I get done and what is my risk here? Thank you for your advice. 

You really needn't be worried and there is no need for testing for HSV or anything else. Even in the most sexually active persons (commercial sex workers, for example), at any point in time most do not have transmissible STIs. And even if your partner were infected with something, STIs are rarely if ever transmitted by fingering or other hand-genital contact, and rarely (if ever) transmitted through clothing:  cloth fibers form an effective filter, even when wet with sexual fluids. As for your "big red spot", no STI can cause visible abnormality or symptoms in under 24 hours, and no STI starts out as a "red spot" on the skin. It seems likely you're just observing minor skin trauma from "a lot of grinding/dry humping" (your words). And testicular pain or other testicular "sensations" really cannot be anything other than an emotional reaction. There is no point in getting tested for HSV:  if you don't have actual blisters or open sores, there is nothing to test; and blood tests take 12 weeks to become positive; and even then the results often are unreliable. I recommend against any testing of any kind.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

Thank you for the reply. I should clarify the red spot is more than just a spot but actually a big bump, similar to a pimple or bite, but it's not open bleeding or watery or anything yet. Do you believe if my penis happened to touched her vagina through my boxers briefly that I have reason to worry? Also you say it could take 12 weeks to become positive, so should I avoid any sexual activity for 12 weeks and then get tested just to make sure? I have been tested before and was negative previously.  

There is no reason to avoid sex with anyone on account of the exposure described or your skin bump, and as I already said, you should not be tested at any time for herpes or anything else.

You came here for reassurance, presumably, and I'm trying very hard to reassure you. Please trust me:  there is no way you have herpes or any STI from the events described.

Equally important in your situation is the information I gave about the near impossibility of any STD based on your description of the contact. You really weren't at any more risk of STD from this event than if you had shaken hands with your partner, or perhaps greeted her as a friend with a brief hug and a light (social) kiss on the cheek. For STD risk purposes, you didn't have sex.

That's two follow-up comments and replies, included with each question, and so ends this thread. I hope the discussion has been helpful and you can move on without further worry. Best wishes and stay safe.