Thank you for the query.
After a laparotomy
it is always possible that hernia
in the incision area will appear. It is because tissues in this place do become weaker. So you should be checked if there is no hernia in this area as maybe it causes abdominal protrusion.
I suggest you to visit general surgeon
and have it checked with simple physical examination.
As it takes up to a year for the scar to completely create, after a year you should be able to exercise your belly without any complications. However you should start your exercises gently and gradually increase the intensiveness of it.
Hope this will help.