Can my intramuscular Brazilian butt lift be reversed through surgery? 9 years post op and experiencing pain

It will not be possible to remove fat from the gluteus muscle with any kind of surgery. The pain that you are experiencing may not be connected to fat grafting itself. It is possible that there was an injury to the nerve branches either with the cannula or consecutive scarring. Only a detailed neurological and radiological evaluation by means of an MRI may help to find the source of your pain. Hope that this helps.

There is some confusing terminology in your post, such as describing fat, as having been injected into your viscera. It’s not possible to remove previously grafted fat Talaris other than subcutaneous fat. In other words, you cannot remove fat that’s been grafted into gluteus muscle.
I’m not sure there is any surgical treatment for the pain you are experiencing, but a thorough work up may be indicated to get an exact idea of where fat is located and try to pinpoint the source of discomfort.
The chance of having successful surgical treatment that relieves your pain may be a tall order. I suggest consulting with the pain management specialist and see if you can find someone to start a thorough work up process before contemplating the surgical solutions of which there are few based on what you described.
Most people do not have chronic pain after the BBL procedure and lower back gluteal and side pain is very common from other ideologies.This is why a proper work up in the hands of sufficiently talented pain experts is appropriate and should be the first step.
You can talk to plastic surgeons about the outcome and about potential revision of the procedure in regards to the aesthetic outcome but I don’t think you’re going to find plastic surgeons helpful in managing a chronic pain.
Best,
Mats Hagstrom, MD