My left butt cheek is indented and smaller. Can I make it rounder? (Photo)

Sorry for your misfortune resulting from "boils". In my experience, an asymmetry (uneveness) of this degree can only be safely, reliably and permanently corrected using buttock implants.  With scar tissue and you looking very lean, fat transfer is unlikely to be sufficiently and survive.   Glad to be of help. 

It is very difficult to determine the exact size and shape implant you will require to best match your ideal butt image without an examination by a board certified plastic surgeon. Not just any board certified plastic surgeon, but one with many years of frequently performing breast augmentation surgery including different approaches, techniques and implant choices. This is because several measurements not to mention your breast characteristics are needed to determine the optimal implant size to obtain your goals. Without knowing these dimensions it would be difficult to make this determination. For example, the existing base width of your buttock will determine, in many cases, the maximal volume per implant profile that you can accommodate. Liposuction of your lower back and fat transfer is also helpful as an adjunct to implants. Using “want to be” photos however are useful if simply provided to the surgeon.

Hello dear!
Thanks for the pictures and provided information as well.
Based on your photos, you are a good candidate for liposuction and fat transfer, to fix your problem and improve your buttocks, 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 :)
 

The Brazilian Butt Lift is a procedure designed to transfer fat from one area of the body, typically the stomach and thighs, hips, knees, and back to the buttock through liposuction. The procedure is meant to reshape, but also enhances the size of a buttock to better fit the figure and provides a perky appearance to rear end.It is unique by the use of the patients own harvested body fat, rather than the use of synthetic material. This allows for a healthier and longer lasting result. Also, buttock implants may be an option for you, if there is not much fat for transfer. Next step for you is to schedule a consultation with a board certified plastic surgeon to discuss your options and goals. Best wishes.