Ok thank u ferret,if the OP can show us an underside of the chin,then I will stick with my first reply of the post .Gular edema is only on the bottom of the neck. If it's bad enough it can cause swelling up the sides. What you have circled in the picture is just fat deposits. It's a well fed chameleon. That's all.
What about that grey spot on the fat pad?dont know if its the angle of the picture taken or the edema in development.
Is it an old shed skin,pigment discoloration or start of fungus ??