Is being pre-diabetic puts me a greater risk for a Brazilian Butt Lift procedure?

Being a diabetic or prediabetic should not be a contraindication for any procedure. It is the associated abnormalities in vasculature, kidneys, heart, … etc that might pose a contraindication. I advise you to check again with your family doctor for the real reason for the non clearance. If it is only diabetes and your blood sugar is well controlled then I advise you to seek another opinion. If there is a major contraindication such as kidney disease or heart problem then yes I might agree that the risk is not worth it.