My pullet suffered severe head pecking injury about 7 weeks ago. We actually thought she was dead. She spent four plus weeks in the house healing, with a topical antibiotic (no pain killer in the antibiotic) and some blu-cote, as well. This pullet (then chick) had the skin completely pecked off her scalp to the skull. Now her skin is completely healed and feathers are even growing back. She still looks scruffy and not quite right on the top of the head, but not grotesque as before.
Moved her to a visible chicken coop with run a couple weeks ago, so the other hens and pullets could get used to her. Just three days ago, let her out with the rest of the hens and pullets in the yard. There has been some pecking, but so far she is OK (must admit I'm nervous being here at work today, not being able to monitor).
So, the chicks will heal with a little time and TLC from these head pecking injuries. Now just working on the reintegration.