Should I take plan B? Help?!

Me and bf had sex. We used condom. He pulled out and we just laid here and kissed. As he was getting up, condom slipped off and his pre-cum dropped a little bit on my lady part and thighs. Is there a chance that I could get pregnant? Should I take plan B?

Edit: also the app says I’m ovulating in 4 days and there’s 11% (medium) risk of getting pregnant