Is the wound on my Penis the reason I can't get hard?

[Rebi445]

This is kind of embarrassing.. but this is how it started.
When I first started masturbating around the age of 12-13 I experimented alot and one time made the dumb decision to put my Penis through a plastic hole (that was not meant for masturbation) while rubbing it back and forth. It didn't hurt at first but after I came I noticed a small plastic nob inside the hole that tore the skin on the side of my penis.
It began to hurt alot and the pain got worse and worse. If I remember correctly, this kept going on for about an hour or two and afterwards began to die down. My Penis did not bleed though and the only visible mark it left was a line
of dark skin on the side of the shaft where it got torn and a red mark on my tip. Also, I noticed that peeing got slightly tougher to do than before, nothing painful though.
Me being a little kid, I was way too embarrassed to tell anyone, so I kept it to myself.
I am now 18 and in the past I had two ocassion's where I was about to have sex with a girl, but both times my Penis didn't get hard enough to enter, despite feeling arroused. In my head I always wrote it off as me being nervous.
I now have a girlfriend. We've tried to have sex multiple times but the same thing happened everytime we tried. The thing is, that I know her long enough that I don't feel nervous or pressured around her, so I kept thinking to myself that it's because of that wound.
Is it possible that such a wound could cause problems getting hard? What do I do to fix it? Should I visit a doctor?
Another reason might be masturbation. I've read that if you masturbate too often it'll cause problems getting hard during sex. Before I got into a relationship with her I used to masturbate once a day, very rarely doing it more than once.
This is a very embarrassing topic to me, any help is very much appreciated. If you have any questions for clarification, I'd be glad to answer them.