All oral sex is low risk for STDs, so much so that many people consider oral sex as "safe sex". The chance a female sex worker (or massage worker) has an oral STD like gonorrhea o4 chlamydia is under 1%, i.e. fewer than one in a hundred such persons. And even when such infection is present, it probably is transmitted only 10% of the time -- and that's for oral sex for a few minutes, to completion. I would judge the very brief and fleeting exposure you had to be zero risk for all practical purposes. The intermittent "itching" sensation doesn't suggest any STD. Assuming you continue to have no other symptoms over the next few days, I see no need for testing -- and if you have a regular partner, I would advise you continue your usual sexual practices with that person without worry.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD