if you don't remember wiping you vagina you should take a pregnancy test just incase and you should drink lots of water
Being a Virgin is no protection - where blood can come out so sperm can swim in. If semen got into your vulva and you failed to wipe it out, there would be a slight cause for concern. The way you describe it this did not happen, so I think you are safe. It’s time to buy some condoms of your own and insist on their use when you are naked together.