In April, my partner experienced a prominent vein develop during masturbation and he has became concerned about it in the past weeks. The vein is on the right side near the bottom and developed where his right hand was. He occasionally masturbates off and on for several hours at a time. He's 25 years old and he says he has masturbated once daily for 10 years. He have been able cut back on masturbation (three times) in the past week and he completely lost interest in doing it, so leaving it alone is not an issue. We have not had intercourse yet either.
He saw a doctor that said it was probably just a normal variation, possibly a varice. His urine test was clear. His erection gets completely hard and everything works properly. I am concerned about a few things.
1. When he masturbated that time, his penis became inflamed, but swelling went down. What would that mean?
2. He was holding the penis and felt the vein become large instantly. Does this indicate anything?
I've been reading up on this and it seems like it might be Mondor's disease (Blood Clot) or possibly a varicose vein. He has pain from the penis vein to the lower right abdomen, up to where the external iliac vein is. The pain (3/10) is resolved by 400mg ibuprofen entirely. He's had a varicocele and mild varicose veins in his legs for 7 years. Varicose veins run in his family.
3. From masturbation, the foreskin has darkened. Will this be permanent?
After he has reduced masturbation, the vein size has slightly decreased and the foreskin is less dark.
4. What damage can excessive masturbation cause exactly?