Symptoms of an oral STD do not show that often and if they do they do not show 1 days after the event. This is not going to be STD related.
Did you ever figure out what it was? I have been having the exact same problem. My throat had been sore and the gland in my neck are swollen, But i have no other symptoms. Its been going on for a total of two weeks now, but for about a day or two it went away, then came back. Im very worried and would like to know what it is.