Mouth ulcers do not cause crooked mouth. Mouth ulcers can cause severe pain, in order to reduce the pain, the patient will avoid rubbing the mouth ulcer lesions through some movements, at this time there may be symptoms of crooked mouth, not accompanied by the soft tissues of the maxillofacial region, teeth, jaws, temporomandibular joints, the crooked mouth symptoms will disappear with the healing of the mouth ulcers. If the crooked mouth symptom still exists after the mouth ulcer heals, the crooked mouth may be caused by temporomandibular joint disease due to long-term partial chewing. There may be other reasons for the crooked mouth symptoms. If the symptoms are serious or persist without improvement, it is recommended to go to the hospital and receive professional treatment as soon as possible in order to avoid adverse consequences.