I was giving oral to a woman.. but she had sex with a guy too at the same time.. right before.. could this little sore on the top of my mouth be a symptom of an std already? I noticed it about 2 hrs ago.. and we were having sex last night around 830p.m

Could be, more likely not. That would be a very quick presentation. I would recommend getting it looked at by a doctor to be sure. As well as getting a complete STD kit done.

Also might want to stay about from the risky Sex adventures.

I doubt it would appear so quickly but if you are engaging in what is considered risky sex I would advise being checked and having some tests run.

You have now been exposed to anything she may carry and all her previous partners as well as anything he carries and all his previous partners.