My 1 guess would be just a good ol´hunger strike. Like the dude above me the guy looks healthy to me. Your chameleon might be bored of eating the same thing, so try giving him something different to eat and see if it snaps him out if it.
I kind if just went through a similar thing with my chameleon haha except mine didn't eat for 5 days and it took a cricket covered in bee pollen powder to get him to eat again haha.
Since you seem pretty freaked out i'd recommened filling out the help form questions so that a person that actually knows about this chameleon type can help you figure whats up.