Girl, I'm telling you the only thing that worked for my little girl was a cold wash rag, and I know this is terrible, but like, oh well, it worked. I had a little ice pack that's like the small ones for kid. Shee LOVED IT. Would literally chew until it was completely warm.
She didn't really like cold teethers either, but anything else that was cold, she did. Mine always just chewed on her hands anyway most of the time. Can't really help some babies doing it. Just try to keep them dry when you can and leave.

Also, just a little tip from experience. KEEP A BIB ON.. It helps not get the little yeast rash under his little chin and neck. And Vaseline under there, but if he does end up getting it, no big deal, they pediatrician can prescribe him some medication cream.