That's a good sign that its smaller after the shed! I don't have a lot of first-hand experience dealing with scabs so I'll defer to more experienced people to answer that.
The one thing I can recommend though is just running your hand over all of the surfaces in his viv in case he discovered something there he got his head cut on. If you find a rough edge you can possibly sand it down, just be careful to wash/disinfect well after to get all of the dust particles from sanding off.
I also have an albino and agree that especially when they are young its hard to tell when they shed. What you could do is make some notes about the behavior around the time of the shed - for example I know my snake is going to shed soon when her activity level declines and she doesn't come out to drink as often.
And like albertagirl said, its totally OK (and even recommended) to not feed right before a shed. Its not dangerous to delay the snake's meal by a couple days until they finish shedding. Its my understanding that these snakes are pretty hardy and can go many weeks and possibly months without feeding if they have to.