How Can Painful Recurrent Cell Overgrowth After Finger Amputations Be Treated?

I had my index and middle finger amputated after an accident almost 2 years ago. the amputation is just below my finger tip. no nail is left. i've had 6 surgeries since that time to remove "leftover cells" that continue to grow causing me pain. is this normal? I'm about to have another surgery to remove the growth caused by these cells. will it ever end?