At the start of the game:
Henry is a teen, with no worries or trouble. Longer Hair and no facial hair, no scars or scratches would be right.
After the attack at his town and loosing his family:
He looks a little older, maybe with facial hair.
In the beginning of the game there will be a quest in the monastery. To “play” the role of a monk he needs a hair cut!!:
After this he has the short hair. For the rest of the game, because KCD will last only some ingame weeks.
At the end of the game after some hard battle, maybe he will look like this:
It´s technical not a problem to give Henry a “progressive” face. I bet this will happen. Everything else would not be right and unexpected (for me).