If your abdominal reduction is carried out by a qualified plastic surgeon, complications are extremely rare and usually insignificant.
Nevertheless the outcome is never completely predictable, as people differ in their anatomy and the healing process may vary from patient to patient. Complications which can occur during an abdominal reduction are, for example, a haematoma (a collection of blood under the skin, which has to be removed by the surgeon), and infection, which must be treated with drains and antibiotics.
These complications would prolong the stay in hospital. An infection with poor healing may result in unattractive scarring, which sometimes makes a second operation necessary to correct the scar. Impaired healing normally only occurs in the case of chronic smokers.

You can significantly reduce the risk of complications by carefully following the advice of your plastic surgeon both before and after a facelift.