Can An Emergency Contraceptive Be Taken When There Was No Sexual Intercourse?

Hello. Two days ago, my boyfriend and I did not have intercourse (I m a virgin) but we did mess around and he ended up ejaculating on my bare leg. I washed my hands with soap & water and without drying my hands, grabbed a piece of toilet paper to clean off my leg. Without thinking, I grabbed the used toilet paper and went to wipe my vagina but stopped after BARELY wiping my clitoris area because I realized the tissue was dirty. I didn t completely wipe myself. But now here I am, freaking out about being pregnant. Can sperm even come off of the toilet paper, onto my vulva, and into my vagina? My period is supposed to come in 3 days. Is this situation worth taking a Plan B pill? Please help!!