Raising an injured baby chick alone ?

There was a clutch of five all brooded by the mother hen. One took a day longer to hatch than the others and is smaller and weaker by comparison (but still healthy). Yesterday, the other chicks began picking at him. From the base of his head and down the back of his neck is raw and fuzzless. We didn't think he'd make it if we left him with the others, so we removed him to a tank. He is very distraught. My question is, will it be safe to move him back with his siblings and mom once he is healed in a few weeks? Or will they be likely to reject him? Will this chick develope the social skills needed to be with other chickens later? Fyi the chick is about three weeks old now and is being kept company by a mirror in his enclosure.