The risk doesn't go away because you haven't had symptoms.
You can still have an infection with no symptoms. Oral sex risk is lower than vaginal or anal sex, but it's still possible. Is there some reason you haven't tested?
You had unprotected oral, so your risks are for gonorrhea, chlamydia, syphilis and genital herpes type 1 (if you don't already have oral herpes type 1).
Syphilis is uncommon in most developed countries, so I wouldn't worry so much about that, but you might still want to test for gonorrhea and chlamydia.