[cypher]

It does sound as though he may be chewing in a an odd way or position that's causing this to happen, I had a Chinese ham who was always trying to get her nose anywhere it shouldn't be & it ended up being permanently red! It never became a problem or bothered her so in the end I gave up worrying about it but if you are concerned then maybe either switch to a different kind of chew treat or limit the time it's in the cage.