Have my fat cells died because all the pressure by sitting and sleeping on my back? surgery done Saturday April 30th at 7 pm

Thanks for your inquiry.  225
cc’s is a modest injection amount of fat, but there should be a difference in
the shape.  The best way to see your
results is by comparing your pre and postoperative pictures.  It definitely helps not to sit on the
surgical area following fat grafting because that can increase the chances of
fat atrophy.  I would follow up with your
surgeon regarding any concerns you might have regarding your final result. 

Thank you for your question. When getting a BBL, the fat cells are transferred in microinjections throughout multiple planes in the buttock tissue so that they can gain new blood supply and live in their new home, providing increased volume and shape to the buttocks. Postoperatively, no specific position is indicated and we do not have any sitting restrictions. The pressure caused by sitting is not sufficient to affect viability of the fat cells and so the postsurgical position depends basically on comfort and any other operations that have been performedYou are likely seeing changes as a result of decreasing swelling. After surgery there is a predictable swelling process that mostly resolves over two months, when the final result really settles in.

Likely a significant portion of your fat has died/not taken due to the pressure.  One of the most important aspects of these cases if offloading pressure for at least the first week to allow vessels to grow around the fat that was transferred much like a skin graft has to 'take' after being applied to a burn victim.  Pressure during this early time frame can affect the results especially the amount that you are describing.  Best wishes and good luck.