Hi Pats,
Sorry to hear that you're looking for revision surgery. I haven't actually had jaw surgery myself - as of yet . However a friend of mine had double jaw surgery with Mr Paul Johnson, who had from what i remember a large, crooked underbite. Seeing her results were actually even the first time i had even heard/seen of jaw surgery and the results really were amazing .
I consulted with him about a year ago in pursuit of fixing my crooked jaw - however this is completely aesthetic as i don't have any real functional problems other than a mild cross bite, and he seemed like a really nice guy. But still unsure if i really want to go through with it.
Whoever you do decide to see i would recommend always getting a couple of opinions but he's likley your best bet.
Best of luck!
Ollie
EDIT: i Forgot to add i came across a lecture by him on youtube when doing my research on who to consult with if thats of any use for you...
https://www.youtube.com/watch?v=EotCgxl5LCo