Why is my face getting fatter all of a sudden?

That's a tricky one. My guess is it's either puberty, or fat redistribution. Everytime I lose weight, it seems like my fat goes to different places. I don't know if that's a real medical phenomenon but that what seems to happen. Whether its puberty or not though, your body is just changing. So unless your having pain or some weird medical thing, I'd just go with the flow. You'll normal out eventually.