Why is my butt still flat at the bottom after 2 BBL's?

Unless your third BBL is being done for free, I would question why you would go undergo the exact same procedure  yet again when the two previous times have failed. This is a common result after BBL and not due to surgeon variation or technique. When the fat does survive it tends to survive in the upper third of the buttock but relatively sparse in the middle and lower thirds. This is a reason why so many patients then choose to go forward with buttock implants that augment the entire buttock, especially giving projection in the middle where it is most desired. Glad to be of help.

To start, congratulations on your amazing weight loss. But if you're not getting the results you desire, you and your surgeon may not be on the same page as far as the look you're ultimately going for. Based on your pictures you are an excellent candidate for both an upper body lift and a BBL to reshape the buttocks. You currently have too much upper pole fullness and require more lower pole fullness to get the shape you want.The optimal BBL outcomes are achieved with: 1) use of VASER liposuction to harvest the fat, 2) a closed looped system such as Puregraft to process the fat, and 3) strategic micro-packet transplant technique. These three processes have demonstrated over 95% fat graft take. This means that your results will be stable as long as you maintain your weight. As an official VASER trainer, I am routinely referred unhappy BBL patients. One of the most common reasons for disgruntled BBL patients is that patients are not able to accurately communicate their desired buttocks goals to their surgeons.  A buttocks assessment tool can be an invaluable tool to communicate to your surgeon the exact buttocks size and shape you are desiring. A Skype or Facetime consultation with a BBL specialist can help you get an accurate recommendation and pricing.
Respectfully,
Arian Mowlavi MD, FACS
Realself 100 Hall of Fame Inductee