A dog may be depressed when wearing a dog muzzle because he is not used to it or feels uncomfortable. This may happen to dogs wearing a muzzle for the first time. This is a normal phenomenon. Generally, the dog wears a dog muzzle several times in a row. The dog will get used to it, don't worry too much.
Tips:
It is best to start training your dog with a muzzle from an early age, so that the dog is more likely to accept it. It is best to choose a more comfortable cover so that the dog will be more comfortable wearing it.