This seems to be more like freckles but they're black. It looks like he's been chewing on a black ink pen, and it has stained his lips with black dots and some of them have run together. And it has only effected the skin on his lips and nose. I have another cat that sometimes gets what you have discribed under his chin and that flakes off and looks like flea dirt.
Georges black dots look like they are a pigment discoloration because they are smooth and exact with the skin.