Breathing through the nose in adulthood and convexity of the mouth cannot be improved.
From clinical experience, if you sleep with your mouth open when you are a child because of adenoid hypertrophy, chronic rhinitis, sinusitis, etc., you will have abnormal maxillary bone development due to prolonged open-mouth breathing, and manifestations such as high arching of the maxillary bones, anterior convexity of the upper teeth, and upturning of the lips are known as adenoidal facies.
Once adenoid face is formed, it is impossible to improve its facial state through ordinary medication, and the abnormal changes of maxillary bone development and anterior convexity of teeth need to be alleviated through coordinated orthodontics and orthoprosthetics in stomatology. Moreover, the intervention time needs to be as early as possible, and the best results are usually achieved in early childhood when the jaws are not fully set.
If the patient is now an adult, although nasal ventilation has improved and he is able to breathe through the nose, the maxillary development has been finalized, so the lip protrusion cannot be improved and restored on its own. It is necessary to go to a plastic surgery specialist for further improvement, including surgery.