STD question - first timer

I gave my bf head a few days ago for the first time. It was also my first time doing it ever. I’m also kind of a germaphobe and am a very paranoid person. To my understanding, he’s only been with one other person and he’s a pretty clean guy. Before I did it my throat was hurting but ever since (I’m thinking from my paranoia and germaphobia) it still has been and now my gums and lips have been burning off and on. I think I’m just thinking about it too much but what’s the likelihood that I’d get an STD and how would I tell if I have one? I don’t really have people I can talk to so feedback is much appreciated.