I am sorry for your unfortunate experience. However- this does occur on occasion and usually- with time- you can get the wound re-closed and expect a full recovery. Looks like you had a hematoma which sometimes is hard to detect in the early post op period. I am surprised that this problem was not treated by your surgeon. I suspect every consultant on this site would have taken care of their own problem and not had the hospital physician deal with it. For now dressing changes and when swelling resolves perhaps a return to the OR for secondary closure should take care of this
Hematomas and subsequent wounds and infection can be complications of tummy tucks. Such a wound looks big but should heal well. Typically even with such a wound only minor scar revision is necessary.
It seems you've had a hematoma complication. Its unfortunate but rarely,a hematoma can happen, sometimes even in the best of hands. That said, in this day and age such complications are imminently preventable and are a rarity. Hope you do'nt have any other pre existing medical condition like diabetes or hypertension. The treatment of a hematoma is drainage, antibiotics and if the wound has gaped, then resuturing under local anesthesia a couple of days down the line. If you have an open wound this long, you may need to be taken back to OR and resutured.