I'm no doctor but I think it could be a calcium build up.
Make sure your chameleon is drinking plenty of water because that could lead to kidney failure. Keep an eye on your chams eyes and make sure they don't start sinking in and also provide plenty of hydration and humidity.
What are your chams eating habits and drinking habits?
What do you feed your cham?
Do you supplement the food with calcium dusting?
Also check out the health discussions on the site about the same symtoms and remedies.
Hope that helps a little