Hello,I am sorry your boy is having trouble.
Problems with the feet are often due to allergies , yeast or bacterial infections.
In many cases oral antibiotics are needed to fully clear the problem.
If she is chewing on her feet I would suggest using an e collar to prevent this. If a dog continues to lick the feet this is often a cause of infection.
If the feet are itchy then oral Benadryl may help. This is normally dosed at 1-2 mgs per pound of body weight every 6-8 hours.
I would suggest having the paws looked at by your vet to be sure there is no infection that would require medication.Your vet will be able to do a simple skin test to look for the presence of bacteria or yeast.
I hope all goes well, please reply back if you have additional questions or concerns