Thank you for your question.
I am Dr Saha, I shall try my best to help you.
It is possible to have injury from oral sex.
This would be present since the act & would gradually get less.
STI like herpes is also possible.
There may not be burning, discharge.
I feel you should take an examination by doctor.
Doctor can advise swab test, if he feels necessary after examination.
I hope this information helps.
If there’s anything else I can do, please let me know.
If you are satisfied, please rate my answer as good or excellent.