Was it all the way out, or a partial dislocation? I lost count of how many times I wrecked my left shoulder, but from what I remember it was 100x worse going out and coming back in than when it just sat there dislocated. Now, on the partials, total misery. There was no healing for me. The bones in the shoulder are all chipped away and everything around it was torn. I'm held together now with screws and a bone graft.
I remember too, watching my father in a hospital bed with a dislocated shoulder. He was in pain, but ok enough. As soon as anybody touched his arm he writhed in pain. They ended up knocking him out to put it back in.
Shoulders are wildly complex. Hopefully Brazeau gets patched up quick and is able to put this injury behind him. Same for Poitras. The mental game with your own body after this sort of thing is really rough too.