If I lost my buccal fat due to anorexia and weight loss, can I gain it back by gaining weight? Is it lost forever?

Hello P,
You have lost weight! Fat loss from weight loss is not irreversible, buccal fat should fill again as you regain your weight. I would recommend Sculptra injections. In the hands of an expert injecting physician, there is extremely low possibility of adverse events, I am not aware of any reports of blindness from buccal injection of Sculptra. Good luck and be well.
Michael A. Persky, MD
Encino, CA

Having had weight fluctuations, should not change your fat distribution.
I suggest first getting yourself to a healthy weight before considering intervention.
You will not lose any particular fat cells from having lost weight previously.
The fat cells simply temporarily shrink.
Best,
Matt Hagstrom, MD