fellatio - cut in mouth - no semen

i recently gave my boyfriend of 4 months fellatio and later realized that i had a cut in my mouth. he did not ejaculated in my mouth. he has had 2 sexual partners in the past when he was a bit younger (maybe 17-19).. but not in the last couple of years (i don't know why this would be important). i know precum has its own hazzards but what are the chances that he could have something and, more importantly, what are the chances that i could catch that something?

[Teak]

You didn't have a risk of HIV.