You have what is most likely a Hemosiderin deposits staining your fat tissues and skin.
Liposuction as a procedure has evolved and improved over the decades. The biggest breakthrough happened in the early 1990s when Dr. Jeffrey Klein did pioneering research on the use of a numbing solution...
Sounds like the surgeon who you selected told you how much they wanted to suction and if they offered you the procedure it sounds like they feel like they can achieve what you are looking for and they are offering. If you dont trust them I would get a second opinion or not go with them for the...
What you have left is pigment from the red blood cells that have now stained your skin. This is not bruising and hyperbaric treatment will not be helpful. Some laser treatments might be helpful.