Doctors usually tell patients before surgery that they can expect some permanent and some temporary numbness. It is often permanent in the triangle extending from the umbilicus down to the upper pubic area (along the incision). The areas from the incision ends, across and above the umbilicus, extending into the upper abdomen are commonly partially numb and temporary.
Some sensation recovery occurs in the first few months, but final improvement can take 2 years. Most patients say they feel normal in about one year.
Remember numbness is decreased sensation. This doesn't affect motion or strength of the muscles underneath.