It may be that your dog is having an allergic reaction. An allergic reaction is often the cause when a dog is excessively licking and/or chewing their paws. Thyroid problems can also cause paw problems as well. It's possible your dog has developed a secondary staph or yeast problem. If yeast you can try some miconazole cream to see if it helps but it isn't a cure for underlying condition.
You can try baby socks to prevent your dog from licking them. You can also give your dog some Benadryl. The dosage is up to 2 mg per pound every 8-12 hours. Start with 1 mg per pound first and see if it doesn't help the situation and provide your dog with some relief.
Here is a site on dog allergies http://www.nhahonline.vetsuite.com/Templates/ContentPages/Articles/ViewArticleContent.aspx?Id=864 http://www.lbah.com/allergy.htm
If you can keep the chewing to a minimum, it might stop once the visit is done if indeed it is an allergy to something there and not present in your state. Hope this helps.