If your friend was my patient, I would advise her that taking the Plan B was an excellent move. If she had already ovulated for this
cycle, there is no concern about pregnancy. If not,
Plan B will delay that. She will need to do a pregnancy test if she does not have her normal menstrual period. There are some current studies that show that there may NOT be sperm in the pre-ejaculate--in which case no chance for pregnancy. Those two are probably the most important factors in your favor.