Maybe parasites
This could be a sign of parasites. I would take the sample and your cham to a vet ASAP. I know in mammals it can be a sign of a perforated bowl which can lead to painful infection and death quickly.
Is his belly puffed and/or hard. These are definite signs of infection.
Hopefully it is the cham equivalent of 'roids, but you need to see a vet.