I might be a little late but with my chick something similar happened, I just sewed her up. Kept it moist with neospirin and a little Chapstick and her scab is smaller than a dime now.
That was the day we found her. This was her the day after.
Skin has now grown back and the skull is covered by a scab smaller than a dime.
That was the day we found her. This was her the day after.