I am insecure about my left butt cheek. It is deflated on the bottom or something?

Your defect could probably be improved with a fat transfer to the deficient area. See a plastic surgeon who does a lot of fat transfers. Good luck.

Hello dear!
Thanks for the pictures and provided information as well.
Based on your photos, you are a good candidate for fat transfer to fix your problem, and I think you'll get very good results. 
l recommend you to make an in-person consultation with a board certified plastic surgeon for a proper answer and to talk about your goals and anything you need to know.
Good luck :)

Thank you for providing photo reference. A BBL would be the best option for you to achieve the shape you desire as opposed to what you have right now. Fat can be removed from your abdomen and lower back region and then reinjected and shaped into your buttocks. This will give you an hourglass figure and an even plump buttocks. Consult with a board certified plastic surgeon who specializes in Brazilian Butt Lifts with whom you can discuss your options and the details of the operation. Best Regards 

Hello, and thank you for your question.  I believe based on pictures alone that fat grafting to the area will correct the appearance and shape.  A traditional BBL is to lift and augment the shape of the buttocks, in your case liposuction would be to slim and shape the waist and back, the fat would then be used to correct the contour irregularity shown in your pictures vs simply enlarging the buttocks.  I believe with a qualified surgeon you can get great results.  An in person consultation will yield the best advice.  Best wishes moving forward.
Dr. Grewal
Beverly Hills, CA