He should recover provided it's not been active so long that it's caused damage we don't yet know about. I'm supposed to watch him closely for the next couple days and rush him back in if he gets worse, or isn't showing improvement by Friday.
Now that the pain med has had time to work, he's sleeping so deeply it's like he's comatose. His breathing is really slow, and he's just sprawled out. He twitches if a fly lands on him, but otherwise is out for the count. The pain med is supposed to work for 24 hrs, so I hope he's less achey by the time that wears off. He should be well rested by then at least.
Since he wasn't yet seizing, that's a plus. The vet said the bacteria invade the white blood cells and prevent them from being able to work like they're supposed to, so a dog can be knocked down by something they'd normally just shrug off. It affects a lot of things if not caught in time. I guess it's something I'll be a lot more aware of now.