Hello! If it's really like what you said, you can go to the hospital for a diagnosis, or teach you a simple judgment method, that is, under normal circumstances, the distance between the two sides of your mouth when you look up is basically equal to the distance between the inner edge of the cornea.

If it is really a small mouth deformity, plastic surgery can be done to correct it, which can meet your requirements.

Simple opening training can't achieve the effect, it can only enlarge the mouth opening, but can't change the distance between the two sides, so it can't achieve the effect. It is recommended to go to a regular dental specialist hospital or the plastic surgery department of a general hospital for treatment.