Maybe and now his sheds on his face is harder to get off? Because the rest of his body shed fine just his face was still unable to lose shed :/
The face is their starting point and if he can't get that chin started that may be it. you may have to help start it if you see a flap next time then let him get the rest if it came off fine.
I'm curious about what's up with the lower jaw; does there seem to be any sort of wound or infection? Do you know if the snake can eat properly? It may just be the picture, but it looked really bizarre to me.
That first pic did seem like the entire snout was short. this shot looks much closer to normal but still a stout head and short mouth. That's why I was guessing glass bumping.
I have a chineese water dragon we got for free/rescued? because he looked smushed on his face form running into glass full speed. He's ugly as sin smashed face and half his tail is a grow back cuz that was gone too when we got him. but the thing won us over had him for years.