Am I likely to get permanent numbness on my chin if I had this with a previous procedure?

You have a not uncommon indentation which occurs from the disruption of the jawline from the sliding genioplasty advancement which was undoubtably combined with a midline wedge resection for narrowing ...which makes this adverse aesthetic sequelae much more likely. It is seen quite frequently....

You would be best served by going to specialists in facial surgery who could evaluate the deformity in person. It seems that you would must likely need a "skin tightening" procedure with possibly additional selective liposuction.

That would be the correct term although in your case may be better described as a hyperdynamic chin pad protrusion which means, rather than dropping down, the soft chin pad bunches up and protrudes. Botox injections would like be effective, although not a long term solution, but could be a good...