I am a virgin & have never had sex. my boyfriend just touched my vagina with his hands (not inside, no fingering, just a touch on skin) but there was a bit of sperm on his hands. can sperm swim from outside to inside by itself and cause pregnancy?

Too far to swim: Basically NO, but that would depend on how much sperm (semen) was on the fingers, how far up the vagina the fingers went, how fertile the sperm are, where in her monthly cycle she is (fertile days vs. nonfertile days), etc... If worried about pregnancy, one can do a home urine pregnancy test 3 weeks later, if no regular period comes.