When we first got Meeju her face smelled like...well only thing I can describe it as a$$.
We took her to the vet and found out she had an ear infection. They said that is one of the symptoms and gave us oral meds for it and her face no longer stunk!
When we took Choppi to get his teeth cleaned we had them neuter him too so he had to wear a cone and also had his front dewclaws removed (poor guy didn't know he was going in for an extreme overhaul!) his face smelled like rotting garbage, but they told us we couldn't give him a bath for 7-12 days til his stitches healed. We bought the pet wipes (as others also mentioned) wiped up his face and also gave his body a quick once over and it was 10000% better.
