Is she just chewing in one specific spot? It could be that something's bothering her in that spot. Have you had it xrayed? Or it might be a seasonal thing. We used to have a dog who would scratch the side of her face raw every summer. We fixed that by cutting the end out of a sock and then putting the sock over her head. She hated it, but it was - for her - preferable to an e-collar.

Speaking of e-collars, maybe you could see about putting one of those on her until the spot heals up.