How can I get rid of an indentation on my buttocks?

Unfortunately, it is not possible to answer your question without any photos. However, please keep in mind that an in-person, or at least a virtual, consultation with physical exam is first necessary before any legitimate evaluation or final surgical recommendations can be made.

Dear thequeenking,
it is hard to tell for sure without an examination. It sounds like you probably would benefit from fat transfer to fill the dent. If you are considering surgery, I would suggest you consult a board-certified plastic surgeon. Only after a thorough examination, you will get more information and recommendations.
Daniel Barrett, MDCertified, American Board of Plastic SurgeryMember, American Society of Plastic SurgeryMember, American Society of Aesthetic Plastic Surgery

Before recommending a surgical treatment, we need to make a diagnosis or assessment.
Without including pictures, we can’t even begin to make an assessment.
The most common reason for contour irregularities on the buttocks is cellulite.
The treatment of cellulite has historically been difficult and limited.
What can be achieved is highly dependent on who you go to and your candidacy for the procedure.
I have found that Aveli it’s probably the best treatment for cellulite to date.
Sometimes adding some small amounts of fat grafting in conjunction can be helpful.
Consider reposting with a set of proper pictures.
Best,
Mats Hagstrom, MD.