Will it cause pregnancy. With water?

Me and my bf were dry humping after sometime he ejaculated and washed with water . After 15 min we started doing it again he wearing his thin cotton shorts, but we can see there was a wet spots which caused by the remaining sperm in his penis or the water we used to clean. So we dry humped with he also in his thin underwear and me in my cotton nighty and underwear, he rubbed his penis inside of the shorts at my anal and near my vagina. We are so scared. That will sperm survive in his penis after 15 min after washing with water ???and the wet spots in his shorts ( sperm or water )will travel to my nighty and then underwear and cause me pregnancy we don't it for less than 5 min. Pls doctor pls give me answer. We are scared. Pls answer.