Sometimes, when they get anxious or have fleas, cats can lick their bellies compulsively. This can go up to your cat having no hair at all left on the zone and even injuring itself, especially as a cat’s tongue is barbed. Talk about it with your veterinarian. He will check that your cat is not bothered by such external pests and will give you guidance to deal with this situation. If this is linked to your cat’s anxiety, he will probably orient you towards a veterinarian specializing in behaviour.