He's been worrying two old mosquito bites for weeks and weeks. They are right on his face and I guess they're going to scar permanently, but even with putting desitin (butch american sudocrem) on 3x a day they aren't getting better as he picks them to bleeding whenever he's going off to sleep or waking up - 3-4x a day.
He picks at all his scabs, it's not just these two, but these are the worst.
As someone who reacts quite badly to any form of insect bite, they can go on itching for several weeks. It could be this that is making him scratch, rather than just general picking at scabs. Try an antihistimine cream on tehm - or even some syrup at bedtime to calm them down.