A makeover is a term applied to changing one's appearance, sometimes through cosmetics. Makeovers can range from something as simple as a new haircut, to the use of cosmetic surgery, to the extreme of the implantation of dental veneers, eye-color-changing contact lenses, and the use of appearance-altering gastric bypass surgeries, providing massive, permanent fat loss in obese persons, and the associated plastic surgeries, such as abdominoplasty, to eliminate the resulting loose-hanging skin folds (the "panniculus").
A makeunder is based on the opposite principle - removing artificial enhancements to a person's appearance to give a more 'natural' look.