Well I'm relieved your friend wasn't DELIBERATELY slamming the drawer on him. But she may have seriously injured him by accident before she realized he was there. Right now he probably needs a vet visit.

Is he shedding his ENTIRE skin off, as in you have the shed skin, every 3 days? Or is part of it shedding and then later another part is shedding? If he is shedding entirely a whole shed(in one full piece you can hold up and see the whole snake's worth of skin) every few days then the vet should be consulted as well.

I'm confused though.. how long have you had him?