Large Pink Bump on Dog's Hind Leg?

It may be related to the biting. Keep an eye on it and if it doesn't go away, check in with the vet. Also if she is allergic to fleas, make sure she is on a high quality flea preventive such as Frontline Plus, Advantage, K9 Advantix. Since she has such an issue, I would highly recommend treating the yard for fleas as well. If she doesn't improve after that, it may be time to consider that something other than fleas is bothering her. Good luck!