Liposuction of the upper thigh just below the buttock causes a double crease or multiple creases.Correction should first be with fat transfer to the buttock crease. It requires a lot of fat, from 200-400 cc each side. I have corrected this in the past.Last resort is direct excision of the buttock crease. The scat is under tension and very visible and very difficult to heal because of tension and sitting
You are correct in that only direct excision of skin under the infragluteal fold and lifting will have any change of getting rid of the skin ell below the fold area. While this does create a linear scar in the infragluteal fold, as long as it does not extend too far to the side it is not that visible.