Poor little thing!
She likely got it hung in wire or possibly a feeder.
I see the upper layer is loose, that may peel fall off on it's own in a few days. The layer underneath is the quick and will generally harden, but I'm sure it's very tender right now.
Personally, I would leave it alone. See that she's drinking and offer her some wet feed to eat for a few days since it will be harder for her to "peck" at feed.
As long as the others aren't bothering her, I would put her back with the flock.