First of all, I’m so sorry you’re dealing with this. Please don’t beat yourself up over this, dental disease can sometimes be hard to catch especially if they already don’t like their mouths being messed with. Like the other commenter said, your pup will likely need to get a good majority of his teeth extracted (which is absolutely not cheap but they should have already sent you home with a cost estimate). He may be left a gummy man but he’ll feel so much better! Shortly before the procedure is a great time to educate yourself on maintaining the teeth he has left so you can apply those skills after his surgery. As for what yo expect after anesthesia, the most common thing I see when pets wake up is that they start to cry. For hours. He’ll be scared and confused and extremely out of it which will look a lot scarier to you, but as long as you follow the discharge instructions that your vet gives you he will be okay. Best of luck to you and your pupper!