Welcome to the forum, @Jools . Sorry you’ve been suffering.
There have been many members who’ve got MAV from trauma including myself.
I suspect trauma has a better prognosis than predisposition. I have largely recovered. Only tinnitus and mild hearing loss remains (which I expect to improve still further)
Unfortunately such injuries are very complex, I suspect, and the symptoms are part of the process of your system readjusting and heading back to homeostasis.
If I’m frank it might take a very long time but there is light at the end of the tunnel for sure!
Keep experimenting with symptom control in the meantime (including medication as required) so you can optimise your quality of life whilst nature does the rest.
I suspect you will be fine ultimately. Hang in there!!!
Patience is a must: I had one symptom, imbalance for over 3 years! But it did eventually go away despite feeling like an eternity and despite feeling like it would be with me forever (it wasnt). My personal diary is here My journey to Hell … and (almost) back. if you are interested, but there are plenty of others in that Category to read and compare.