Having a shed in one piece isn't a big deal, as long as it all comes off!! Mine usually have one main piece and then the sides of the head are kinda here and there. I always check to make sure the eye caps have come off.

Wow! I've yet to catch mine during the shed. They usually do it inside their humid hides....little boogers!

I think I would be more worried about what caused the scratch in the first place. See if you can identify the problem and remove it. I think it's ok to treat with neosporin, but I'm not positive. Haven't had to do any doctoring on the snakes yet and I can't remember if it's ok or not.