I have a few flat spots on my butt after BBL. Is this normal?

An important question. There can be some contour changes that occur as your swelling resolves. Im glad youre following your instructions since this will help the swelling resolve as quickly as possible. It takes several months for the swelling to resolved although much of the swelling resolves over the first 12 weeks. 
Best wishes,
Dr. Jan

Hi there,
It's ok to have concern about results but you are still in the early stages of your healing process. Just be patient and make sure you follow every step your surgeons has told you do post bbl. Best of luck!

Hello dear!!
Thanks for the question and provided information as well. 
You are still early on the healing process, it can take up to 6 months to see your final results, so please be patient. At the stage you are in, swelling is very normal.
Unfortunately, without pictures is very difficult to give you a proper answer. If you have any concerns, please follow up close with your plastic surgeon.
Good luck :)