It is possible that she is nibbling the paw herself? My brother has a collie and she cut her paw, he tried to clean it and dress it but she just spent all her time nibbling at her paw and in the end she made a right mess of it. She was taken to the vets who said it would be ok and probably gave some treatment but he had to buy some of those walking boots to keep her from doing anymore damage. It did work thankfully.
