should I take plan b

I had sex with a friend from high school. I'm on birth control, and we used a condom. well when he went to pull out the condom got stuck inside me. not all the way, but partially. he says he didn't cum on me but it was on my thigh. should I be worried?? should I take plan b to be safe?I'm 21 and I'm a full time employee and student and can't afford having a child.