So you can't test for anything until at least 5 days have passed, so you have some time to see if it's just irritation or trauma from the rough oral.
You can get gonorrhea, chlamydia and NGU from receiving oral, and you can test for those at 5 days. Oral sex is lower risk than vaginal or anal, and most experts think it's low enough risk that one encounter doesn't warrant testing without symptoms.
The chances of it being irritation or trauma are at least as good as it is an STD, if not better.
There's also a chance of getting syphilis from oral sex but syphilis is far less common than the others, and you wouldn't have symptoms until at least 10 days - the average is 3 weeks, and that is a painless, round sore. It wouldn't give you symptoms like you have. It's also uncommon in developed countries like the US, UK, Europe, etc.