Under normal circumstances, dogs’ noses will be dry when they sleep. Because dogs do not lick their noses with their tongues when they sleep, their noses will become drier. This is normal and there is no need to worry. When a dog is awake, he will often lick his nose, so the nose will be relatively moist. If the dog's nose is usually dry, then the dog may be sick. It is best to take the dog to the pet hospital for examination to avoid delays. illness.