Could Taking Postinor-2 After Having Sex Prevent Pregnancy?

Hi I actually had a foreplay with my boyfriend and he had a condom but during the foreplay his condom broke and the sperm was spread on my thigh close to my vagina and he quickly withdrew but I had to take postinor 2 just to be safe. I hope I am on a safer side. I need your advice p.s am a virgin so am scared