Newchin, I'm sorry about what you've been through. No surgeon in their right mind would ever consider 'dental chair' bone shaving.
I too had a botched sliding genioplasty (a huge, grotesque advancement) a couple of years ago. I went to Thuau for a revision, but - when all was said and done - there was no discernible improvement. In my case, he wasn't honest about that fact and I was given the run around for a year prior to my surgery date.
IMO, you need to see someone who is well-versed in complex facial bone revisions.
The good news is that four months after my failed revision, I underwent surgery with a different doctor who reversed the genioplasty by 5-6mm and moved it upwards. Admittedly, my chin is still a (significantly smaller) mess, but prior to that I looked totally disfigured and was in constant pain.
I've managed to improve the situation further with Botox injections into the mentalis muscle as well as injections of phosphatidylcholine and deoxycholate to remove botched fat grafting, which was shoved all over my face by some other incompetent sociopath.
Regarding the bone paste that's intertwined with the muscle: dilute kenalog injections may melt the scar tissue that's formed around it (most permanent fillers become encapsulated) and reduce the bulk somewhat. However, the kenalog MUST be reconstituted first. The surgeon who massacred my chin used 40% kenalog in my upper lip, which atrophied and dented it.w
HA is regularly used in facial bone augmentation - it's definitely not an oddity, but permanent fillers (or 'semi-permanent') are - on the whole - bad news. My hunch is that a face lift approach would be needed to extract the HA paste - this is what I was told about my fat grafting. Since your area of concern is a relatively isolated one, I'd opt for dilute steroid injections and camouflage the remainder with hyaluronic acid.
Again, sorry to hear about your situation. How long has it been since you saw Mommaerts? I was told that nerve injuries can take up to two years to recover. If possible, see a neurologist and get checked out.