I Have Some Necrosis In My Cheeks From Artifill Injections

I have some necrosis in my cheeks from artifill injections many years ago. It's now surfacing and leaves a hollow, dark mark on the side of my face, mid cheek. I've had filler, which has helped, but it doesn't hold to well because it's difficult to get a needle into the damaged tissue. What else can I do? Can I have it surgically removed and if so where?