That`s good. Just make sure he doesn`t get overly disturbed during the day (unless he`s up and about) as I`m finding even chinese hamsters like a routine and like their sleep during the day! My female likes attention after 7:30pm ish.... and even then I let her run around my bed with fleecy blankets and soft furnishings. If she gets a bit aggitated, I let her hop into her fleece pocket toy and carry her gently back to her tank and let her scurry about, feeding her little hand-held treats.
Arro is still young, so it`s essential that he is allowed to sleep during the day, or at least, not disturb him while he is sleeping!
Hopefully his scab/skin will heal up well and his fur should grow as normal. Give him a sprinkle of dry porridge oats in his dish.
I use Tesco organic jumbo oats, Buckwheat and Kallo organic wholegrain puffed rice as healthy additions to Prinny`s mix and I feel these help when a small animal is in need of some extras. All are available from Tesco.