Could ejaculation through clothes cause pregnancy

Patient: Iwas wondering if it is possible to get a girl pregnant by dry humping. Because I was wearing boxers and jeans, she was wearing spandex and a thong. When I ejaculated The sperm soaked through my pants and I noticed her vaginal area was soaked as well. About 8-9 hours later I got her plan B. I was wondering of there is a possibility, and if so when should i check to see if she’s pregnant. This happened around the 23-march, and she told me her period is at the beginning of the month. Please help, im very worried! thank you for your time