Hi
I have a 13 week old puppy who has undershot bite her bite was correct at 6 weeks and 8 weeks it gone undershot any advice if it would correct or how to help

I'm sorry but there's nothing you can do. The lower jaw always develops for a longer time than the upper, and so if a pup is undershot it always will be, whereas an overshot jaw might come right with time. A pup who has a tight scissor bite at 8 weeks can be undershot when the teeth change, but one who is undershot will never get a scissor bite.