I had sex with my boyfriend last night. We used a condom, which did not break, and he did not ejaculate. We then had oral sex, but as he moved, a drop of cum dripped on the outside of my vagina. Since I was lubricated, I am not sure if a little bit or anything went in, but it might have. Just to be safe, I took plan B- the one with the two pills, and I took both of them at the same time- around 15 hours after. However, I am on INH medication for latent tb as a preventative measure. What are the chances that I will become pregnant? My period just ended around February 1.