Really cannot tell anything from the picture, but it looks like the jaw is maybe extended. Does your Angelfish live alone or does he/she have other angels in the tank. Sometimes angels will fight with each other by grabbing each others mouth, this can lead to a dislocated jaw. My angels fight from time to time but I have not yet personally encountered this issue.
The first step would be to try and get a better photo, and if you add a better description of the tank conditions, ie water parameters, and the tank and other fish, we might be able to give you a better diagnosis.