Does a BBL revision surgery mean they will re-add more fat if there was severe volume loss?

Ideal candidates are at a stable weight,  in good health , and have excess fat in some parts of the body and too little in other regions.  Gaining weight before the procedure is to no advantage and when you lose weight again the fat cells will shrink just like the donor site fat cells.  Typically, the transferred fat results in a significant increase in volume of the body site being treated.

Thank you for your question.You should talk to your plastic surgeon exactly what his/her BBL revision surgery mean.  But the usual circumstance would be performing more liposuction and harvesting more fat for transfer to the buttocks.  Usually you should expect about a 30-50% re-absorption/loss of the fat transferred, so in my practice I usually over fill the area anticipating the volume loss in the first 3-4 months.Thank you

 A revision can mean several things. It can absolutely mean just added more volume. Remember that you again will experience some volume loss post op (in my hands this is ~30-50%). 70-80% seems high, so you may want to ask about the technique used as there may be things that can be done differently to hold on to more volume this time. Also, a revision may mean just filling in dents like the one you mentioned or changing the shape. Make sure you have an informed conversation with  your PS as revisions can be more difficult and you want to make sure that your expectations are going to be met before signing up.