Do you know if your chin was in a fight? (If so you may be able to clean it yourself if the bite or scratch is minor) If not you may be looking at conjuctivitis, or the roots of the teeth growing into the sinuses causing pressure and swelling, or even an upper respiratory infection
(watery puffy eyes are one of the first syptoms). Either way I'd say go to the vet, it can't hurt. Also what dust bath
are you using? If the vet can't find anything wrong, some chins are allergic to Sunthing Dustbath because it contains fuller's earth.