my 2 year old border collie x husky has been chewing his back feet, one had a like a little scar on it that I've only just realised I thought that might be irritating him & on the other one its like a few layers of the padded bit has come off.. they're also a bit rough.. I don't want him to hut himself or anything. When my mum was younger she had a dog that kept licking his paw that much it was going to be amputated then he started on the other foot so eh was put down... please help