Hi Anjac,
Knowing nothing about BA and it's complications (yet), I do have some unfortunate experience with nerve damage. There is always hope, but at this moment in time, especially after this length of time since your BA, I believe you have as much recovery as you are going to get. However, there are things that you could try, but it may take time and drive you crazy, but from experience, the more you use/stimulate something on your body the better the neurological response from that area. This all depends on what undamaged/partially severed nerves are left in that area. What you are trying to do is strengthen the signal that the nerve carries. The more the nerve is stimulated (or whatever the technical term is) the more the brain will pay attention to it. In effect, getting a stronger signal.
In your case, especially after all this time, it may not work as chances are you may have stimulated those areas enough, however, like I said, there's always hope and giving this a try costs nothing only time. Keep at it. Like with all things nerve damage, what you gain from repetitive use you can also loose. If you get an improvement, you have to keep doing what you did to get that improvement or you'll loose it very quickly.
I don't want to appear negative, I just wouldn't want you to waste your time looking for answers on the internet which is full of people peddling false hope.
Nikki