If he is still eating/drink, pooping/peeing and everything normally, and no signs of being sick (acting lethargic, fur chewing, abnormal poop, drooling, weight loss, etc), it could just be he got a bit depressed when you didn't interact with him for a couple weeks. They are social creatures so if he is an only chin and you don't have anyone else that spends time with him, or even if you do but you are his person, that can make him feel sad. I also don't know if you have him in your room or somewhere else, but if you have been keeping the room dark all the time just like with humans not seeing any sunlight for a couple weeks can make them a bit depressed.
However if that is all it is he should go back to normal with in a day or two once you are back to your normal routine. I would keep a close eye for any sign of issue though, chins are very good at hiding illness and pain so if you notice anything off it's a good idea to get a vet check just to make sure everything is ok.