This morning, our 1/2 long haired chihuahua 1/2 yorkie 4 month old puppy woke up with puffy jowls/jaws. He looks like he is puffing out his cheeks holding his breath. This happened overnight as he wasn't this way last evening. He doesn't seem to be in any pain and is eating and drinking. He isn't spunky like he usually is however.
Has anyone ever heard of this? I've attached his picture that I just took showing his puffy jaws.