Reassurance?

So me and my boyfriend had sex today and it was great. When I was riding him the condom came off inside of me(this has happened one other time why I was riding him) I just started on the birth control implant but I’m unsure if it has had time to really take effect yet. Anyways, we continued having sex because both of as were so close to finishing. He flipped me over and went in from behind. He pulled out right before he came. He didn’t come inside me but I’m afraid somehow some of it maybe got on my vagina and got in somehow (I’m 15 by the way) please don’t say anything about my age. I know I’m young