Male 8yr Shorthair w/Missing Fur and Rash

[karona]

Hi guys. I have a neighbor who discovered her 8 year old shorthair cat had a clump of poop stuck right on his you know what. She pulled it off and discovered that he has a ring of missing fur there and the skin is red. It appears that there is more poop matted into his fur back there and he hasn't been cleaning it.

I also noticed that his mouth was hanging open and I recommended that she get him to a vet to have his teeth checked. In the meantime, I promised her I would ask you guys for any advice as to what she can do to make him more comfortable until he can get treatment. She'd also like to know if she can put anything on the skin for now.

Thanks!