What Are The Chances Of Getting Pregnant Without Penetration?

So my boyfriend and I were messing around. He had already pre came in his boxers but some amount of time later his bare penis touched my bare vagina while we were kneeling facing each other. There was no penetration. He wanted to lay down and continue but I told him it made me nervous. We then kneeled again and he put his penis back in his boxers but we still continued to touch, there was just a layer of clothing between us. Then he accidentily slipped out. I do not recall if he put it back in or not and we continued. I told him that that made me uncomfortable too. Then he fingered me (he did rub where his penis had touched). Is it possible that sperm from the pre cum got on my vagina? Would there still have been sperm on the tip of his penis? Is it possible that I could be pregnant?