I developed hard vein on my penis from the base when it reaches the op it splits into 2 parts its hurting a lot
Penile vein thrombosis, had the same thing, rough sex. Takes a long time to go away, sometimes months, no sex, no masturbation will help healing time. For discomfort try using aloe vera gel and wrapping penis in soft gauze, not too tight, got mine early March, 2 months and it's almost gone. Did see a urologist and this was his diagnosis, told me it would take months to heal, if you need to have sex use a good lubricant.
I am actually looking on the internet right now to see about a problem I am having as well. On the top, closest to the pelvic bone(pubic region), I have what seems to be a y-shaped area of veins where one vein from my body is becoming 2 twards the tip of my penis. 8=-
The hard swollen vein on penis can be due to a clot in this vein which is causing swelling and making it prominent. It is called sexual trauma. It can cause pain as well. I advise you to visit a doctor and get treatment to avoid future complications.