What is the risk of pregnancy with dry humping and plan b taken

My girlfriend and I were masturbating each other, and she asked me if i could rub near her vagina. I rubbed near the clit, and wasnt even near her when i cummed. But we panicked, because we dont know if a drop or two of semen fall near her vagina. She took plan B, but im still worried. She has irregular cycles and her period ended the day before this happening.

Also, don't know if it helps, but it was my second ejaculation, and i had pissed after the first one.

Please help me