According to your description, the child is now an adult, and this malocclusion can only be changed by combining surgery and correction. Surgery can only remove a part of the mandible to make the mandible retreat, and then use corrective methods to replace the teeth with the normal jaw covering your relationship, but there is no good way to change the shape of the maxilla covering the mandible.

This kind of operation and correction is difficult and can only be done in general professional stomatological hospitals. Therefore, it is recommended that you take your child to a large stomatological hospital to consult some specific surgical methods and correction programs. After a series of inspections, it is determined that the basic cost will be around 20,000-30,000 yuan.