Worry!!!

I'm kinda of worried. The other day me and my boyfriend had sex, he pulled out seconds before he comed and it was very close to my vagina he said he felt it go on to material and thinks it all went onto the towel.... However I'm still concerned. I grabbed the towel and got rid of the come that was there. Should I be worried? (Mum doesn't know that I am sexual active and wouldnt be happy if she knew I was)  Any advise?