It appears (photo not extremely clear) to be wht is called a "wry mouth". Sometime it can be corrected while the bones are still soft in the first day or two of life by actually manipulating it into correct position several times a day. I have seen 2 mini horses with such, presented on a forum for advice, and this is what was offered. One did this & bandaged it a couple hrs a day like you would a soft splint, it did straighten to 95%. Owner kept it and it did fine.
It could be a cleft deformity, also. A vet could tell with a visual.
Sometimes in utero they are squished and come out crooked.