I went back to the store he came from and found out that they took him over to "their" vet, rather than the specialized reptile vet they're supposed to use for every sick/injured reptile that comes into the store. That was pretty upsetting to find out...
But anyway, yes he's been just as active as all my other snakes and it looks like the injury is starting to scab. Also got his first meal in him, it was an assist feed but the moment it was in his mouth he pulled it down right away.
I have another hatchling that has been assist fed for a while, and his response was much better than hers was. So I'm hoping these are good signs and maybe his next meal or two he'll take on his own. Fingers crossed!