I gained weight after my j plasma and bbl how can I get back to my pre op body? (photo)

In most cases of weight loss, the buttocks and other areas with stored fat will become smaller.  The fat will not move, but losses in weight will distribute differently. The fat that lives in the buttocks from the procedure will get larger with weight gain and smaller with weight loss.
Kenneth Hughes, MD, ABPS Board Certified Plastic Surgeon
Los Angeles, CA

Dear yashna0991,
most plastic surgeons recommend their patients to keep their preoperative wieight in order to get the best results. You will likely see your weight gain in a uniform distribution after a fat transfer to the buttock (Brazilian buttock lift). The weight or fat that you gain after surgery will not necessarily all go to your buttock area. Similar to weight loss, It’s important to realize that weight loss will affect the entire body, but it may affect the buttock in a more pronounced manner.
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

Hello dear!
Thanks for the question and provided information as well.
After a BBL, you lose or gain weight in the same way as before. So the answer is yes, if you go back to your previous weight, you should see your previous results, but I encourage you to maintain a clean and healthy diet, along with exercise.
If you have any concerns, I suggest you to follow up close with your plastic surgeon.
Good luck :)