Is it permissible to perform surgery to treat a deviated septum, reduce and improve the shape of the nose, knowing that a large nose negatively affects a teenager's self-confidence?

It is not permissible to reduce the size of the nose through cosmetic surgery unless it has a disfiguring defect that people find repulsive and ugly, or if it causes pain and harm. However, if it is merely an ordinary large size that some people dislike, then it is not permissible to reduce it. The same ruling applies to a deviated septum.