Dog depressed after injury???

Our 4 month old German Shepherd mix got out of his crate yesterday morning. A clean casserole dish was on the stove and he broke it and bit a piece, cutting his lip and tongue. The vet wasn't overly concerned. Said he most likely didn't eat a piece because if he did he would be in a lot more pain. She said he was "sore and pouting". After the vet's yesterday, he drank some water and drank some food. He was obviously a little sore and wanted to sleep, but happy. Today, he is hardly drinking, refusing to eat, and is just not himself. He usually loves our walks and we play in the living room. He kept sitting down on the walk, and lagging behind on the leash, like he didn't want to be near us. He doesn't even want us to pet him and acts scared of us now. Is it possible he blames us for his injury...or is something else going on???

Think you need to get him back to your Vet ASAP. He may indeed have ingested some glass. Please get him seen - most Vets have 24 hour cover

I agree. The vet needs to reassess and quickly.

So the vet did x-rays after we took him back. Nothing in his stomach. Definitely did not eat a piece of the casserole dish. He has drank a bit more, and eaten a tiny bit - like 1/2 cup in 36 hours. The vet says he views the injury as our fault, and this is why he is acting so differently. How do we get him to trust us again?? Like, it wasn't our fault. He broke out of a locked kennel...

I'm afraid your vet has little knowledge of how dogs think. Dogs don't hold grudges and for your dog to blame you would require an enormous amount of reasoning.

If your dog was showing a fear reaction, it would be around the cage or the stove as both areas are where he had the incident.

Keep a vigilant eye on him and if you are still not happy with his behaviour or eating, take him to a different vet for another opinion

I don't think he has any fear towards his crate, because he doesn't want to come out of there now. In my opinion, he figures he got injured outside of the crate so the crate is where he wants to stay because he figures he is safe in there. My biggest concern is that his tongue injury has mentally or emotionally scarred him. Like, usually when I come home from work he is so excited and happy to see me. I let him out of his crate, we go for a nice long walk, then come home and play fetch or tug. When we came home from work he was in his crate looking scared, and wouldn't come out when we opened it. We had to basically pull him out. When we went outside, it almost felt like we were forcing him to go on a walk. We cut the walk short in fact because it was very obvious he just wasn't enjoying it and wanted to get away from us. When we got back home he went back into the crate on his own and wouldn't come out for the rest of the night.

Many dogs tend to hide (denning instinct) when they are ill or hurt so wanting to be alone and in his cage may be because of his sore mouth and this may disappear as his mouth gets better.

Keep a very close eye on him and monitor his progress

He's had a fright and his tongue hurts, he doesn't know what happened except he's in pain. Do dogs hold grudges? I wouldn't like to say tbh, if you saw the way one of mine reacts to having drops put in her ears, I think you'd say they do as she acts as if I've tried to kill her. That said I just carry on as normal and she comes around and will come for a cuddle in her own time.
So you've not done anything wrong, give the dog time and space to realise this in their own time. No fussing and certainly no pulling him out of his crate.
I think your Vet is talking out of his ar$e tbh. Just keep an eye on your dogs eating and drinking, maybe offer him something special such as roast chicken but just put it in his bowl and leave him to it to see if he eats it, as any dog feeling well would. If he shows no interest I would be concerned and seek a second opinion. Did your vet give him any pain killers?

No pain killers no. He came out of his crate on his own a little while ago and went to the door to go out. We took him out and he was rolling around in the snow which is normal for him. So we were happy to see that. We were cutting up some roast pork for sandwiches and he kept looking at it, so we did offer him some and he gobbled it up. He is still hurting some, but he is coming out of his crate a bit more.

I think you've found the answer, he's in pain.
Other than that he's behaving pretty normal.
I would have expected painkillers for a couple of days at least.
Sounds like he's getting back to normal slowly.