Bishon foot chewing

Question
why would my 7 month old Bishon always chew on his back feet. They are all pink, even his fur.  He will do this for 10 minutes at a time.  I try to get him to stop, but he won't

Answer
I would think it was his way of telling you there is something wrong,have it checked out by a vet to make sure it isn't medical and then my next guess would be he is bored and has become obsessive about something he did one day to relieve excess energy and entertain himself.