Hello,
Im not sure what is causing the facial swelling but i would be worried about it continuing and possibly causing trouble with breathing. As long as that is not happening it is probably not an emergency.
My first guess is an allergic reaction (for example and spider bite or vaccine reaction), but, it certainly can also be due to dental disease or recent dental procedure.
I recommend you see your vet about this.




















To add: This started about 2 years ago but has gotten progressively worse over the past 6 months- 1 year. We have switched his dog food brand to see if that would help but he has always been on lamb and rice as he has a chicken sensitivity. I have tried powders, drops in his water, cleansing wipes, and raw hides with CHG. Nothing even touches the smell. I would describe it as a decaying wound smell.
@kristamagnifico