Hey dude, old thread I know. I’ve done exactly the same as you describe however mine was done by leaving a **** ring on for hours. No pain just enlarged veins! How did you get on with the issue?
UPDATE: it's been nearly a whole month and the vein is still the same... I have noticed that it only sticks out and bulges when I have been sexually active and lasts about a day or two, then it subsides when 100% flaccid... until I get an erection again and it reappears. I went to the doctor a week after this all happened (just after i posted this thread) and the lady said it was normal (she used the example of the back of your hands when it's warm, the veins stick out) which was not entirely helpful because the vein never used to be there until I had that accident with the pump. Is there any way to reduce it back to normal the way it used to be? Do I just try and avoid sexual activity for a few weeks or something?
From what you describe, it sounds like your veins have expanded from your use of the penis pump, and that is normal, since everything within the pump cylinder will expand due to the vacuum created when used. This should not be a problem, but you should not go "too far" with the pump and overdo it by over-pumping or by using it for too long of a session.