What is the possibility of pregnancy?

So today my boyfriend and I were fooling around, and he started masturbating with his right hand. Then he ejaculated and he wiped it up with tissues with his left hand, then about five minutes later he started fingering me with his left hand. I'm really worried that some semen could've come from the tissue onto his fingers. I've read some other posts here saying that sperm die 3 seconds after being ejaculated but I've seen in other places that it can live for up to three hours. I've also heard that there's a very slight chance of pregnancy if the semen isn't actually ejaculated into the vagina, but I'm still really worried. I'm only 17 and I feel like such an id**t for not thinking of this in the moment. Please reply quickly, and only serious comments please