Surgery is not an exact science. Sometimes the results of surgery may not be as good as patients would like. Sometimes revisionary surgery can improve the initial surgical result, though this is not always the case. Any surgery has some risks associated with it. All procedures include risks of bleeding and infection, and specific procedures have other risks specific to them.
Rhytidectomy includes risks of nerve injury or skin loss.
Abdominoplasty also includes some risk of skin loss. Smoking increases the risk of skin loss with both rhytidectomy and abdominoplasty. Any patient considering aesthetic or cosmetic surgery must be aware of these issues.