If you want to resurrect your victim and you play on PC, you can do it.
You need to find the reference ID for the victim first and write this down.
In your game, open the console and type in Prid (Ref ID) and press enter. (Ref ID) is the reference you found for the NPC.
Now type and enter this command: MoveToPlayer This should dump the corpse at your feet.
Finally, type and enter this: RecycleActor
This should put old Crescius back on his feet as fit as a biddy. You can now exit the console.
If you're playing on a console I guess you'll just have to bite the bullet and go to a save before you walloped him or flayed him with magicka.