I had liposuction 6 months ago and up with a few contour irregularities. They look like mogul-type lumps, not dimply like cellulite. My plastic surgeon said he could do a touch-up with a cannula that resembles a cheese grater, but not remove any more fat.
He said this would help smooth the lumps. But he also mentioned that one complication of using this instrument could be damage to the blood supply to the overlying skin. He hasn’t seen this personally, but it does worry me. Is this a good procedure to smooth out lumps, and are the risks to the skin worth it?

A: It is important to know whether the bumps are excess fat or post-liposuction scars.

The bumps you are referring to could be either scar tissue that has formed after liposuction. If that is the case, time and massage should provide some improvement. A persistently hard scar may respond to corticosteroid injection, however, this injection can have its own set of complications such as tissue atrophy and telangiectasias, so not a great choice.
If the bumps are due to under-suctioned fat deposits, then liposuction with a small cannula could be helpful. The closer these deformities are to the actual skin, the less likely it is to achieve excellent correction.
Being prudent about revisional surgery is very smart. In the case evolving scars, time is usually on your side.