Popped Vein

About two years ago my wife and I "were trying to get pregnant". Anyway we could not. So we were going through the whole do it every night thing. One night after an intense session, I noticed that a vein that was not there earlier that day was now bulging just below the head of the penis. I thought I caused a blood clot. I was very worried. It was soft and I could move it with my finger. after about 2 weeks I had to go to the doctors because I was driving myself crazy thinking that it was a clot and that it was going to travel to my heart, or somewhwere else in my body.
The doctor told me it was caused from roughness and that I basically injured my penis. After two months it was totally gone. One day it just was not there.
I am sure this is your case as well. The body is an amazing thing, and it will heal
itself. So stop worrying about it. But I would go easy until it is gone.