Erection more difficult to acquire, not as hard or big as it used to be

[penisissue]

I'm 21. A few weeks ago, I masturbated a little too long and when I finished, it hurt very briefly. I started to notice a few days after though that my penis was taking longer to get erect and wasn't getting as hard or big as it used to. It also is pretty sensitive when it gets erect. It's as if blood is having trouble reaching the "phallus". I discovered an indentation on my corpus spongiosum (on the underside of my penis) not far from the glans and it seems like this indent may reach farther around the girth of the penis. It seems this indent may have something to do with the difficulties? So in conclusion, the penis is just not getting as hard or big as quickly as it used to and it is sensitive when it does get hard.

[GuitarRox]

You said you were too rough masturbating and that started the issue.  The penis can get hurt like other areas of the body.  Bruising, etc.  And like other areas of the body, it takes a little bit to get back to normal.  The indentation may be related to Peyronies disease or developing peyronies.  This is basically a big term for scar tissue after injury to the penis.  If it builds up enough, there can be a curvature in the penis.  https://www.mayoclinic.org/diseases-conditions/peyronies-disease/symptoms-causes/syc-20353468  It really is most often in older men though.  If that is what happens, this would be the acute phase and will last just 2 to 4 weeks most likely.  

Of course, this is speculation and you probably should see a doctor to confirm anything. And understand too that our mental thoughts also impact things like erections.  If you are worrying about this too much, it will cause the issue to be worse.

I'd try not to worry, see if it is gone at the 4 to 6 week part and if not, check in with your doctor.