Is Pregnancy Possible Through Non Penetrative Sex?

Hello. I have a concern. I am 22 years old. When I was 12, I had a surgery to create an opening in my vagina in order to my menstrual blood to finally be released. Any who, I am a virgin still. Recently, my boyfriend and I got too physical. My boyfriend started “humping” me. I was wearing thin lace underwear but he was naked. Then he pointed out that my underwear was wet. He was claiming that I was me who was wet (I was not having an orgasm, I guess I was still in the process of reaching that point). I was saying that he had gotten my underwear wet…bottom line, we didn’t know who’s discharge it was. I was pretty sure there was no penetration (since I was wearing underwear of course). But since my underwear was wet (whether the discharge was from me or my boyfriend), is there a possibility that I can get pregnant? Is that surgery that I had back when I was 12 increase my chances of getting pregnant due to surgical opening?
Another question? Because I had that surgery, does it mean that when I lose my virginity, it wont hurt as much? Can someone tell me what kind of condition I had? And what anatomical part it is that was actually surgically opened to release menstrual blood?