Hi, no thats not a symptom of any std but would appear more fungal related or it may be natural that your just noticing now out of anxiety from the oral.
In the years ive been advising here id say 70% of the questions and symptoms are all anxiety related. We start to notice things, feel things and even imagine things and its even worse with those that have visited a street worker. Many people briing up things now when the affair took place years ago. Oral sex is very low risk activity and if the oral was not a "deep throat" oral, where the penis reached the back of her throat, the risk is as close to zero as one could get.
Ok I didn't even know that thank you
Oral sex could cause a fungla infection so maybe have a doc take a look since its troubling you. Not much other than fungal.