I have used a muzzle for Chewy just to cut his nails when he was younger because he would bite.
It isn't pretty. They pant they feel upset, and I don't think they can drink and there is NO EATING!!! You can't just muzzle a dog for long periods of time.
Muzzles have their place when ALL ELSE FAILS.... When a dog is biting.... We ony used ours a few times and then Chewy decided not to bite any more...
try anx pen. Or a create.