I had my BBL 12 days ago and my butt is flat in the center and all the fat is up top. Does the fat drop and shape come later?

Hello dear!!
Thanks for the question and provided information as well.
You are still early on the healing process, it can take up to six months to see your final results, so please be patient. At the stage you are in, inflammation, discomfort and irregularities are normal.
If you have any concerns, please follow up close with your plastic surgeon.
Good luck :)

Greetings and thank you for the question. You are still quite early in the postoperative period, and things will change over time. Remain patient as postoperative changes  can occur for up to 12 months after a procedure. Best wishes.