Yes it does take a long time. I am currently 14 months from acoustic trauma that caused tinnitus and hyperacusis for me (exposure to a powerful external alarm sounder for maybe 10 minutes) It has faded 90-95% from what it was, hyperacusis completely gone.
If I concentrate on it I can hear a buzzing electrical sound mostly in the left ear but compaired to where I was this time last year it's almost gone and continues to improve.
I don't have issues with loud noise any longer although I will forever be careful with loud noise after this experience.
After the acoustic trauma everything sounded distorted, music sounded terrible, I couldn't hear bass, everything sounded broken and full of treble. Even my balance has been affected.
Now, 14 months later, things are back to normal, no distortion and music sounds full and rich again. Balance appears to be back to normal.
The improvement was very slow, a good year before things felt normal. It really was a terrible experience but thankfully much better now.
Dont believe the 3 months, 6 months time frames quoted by doctors or websites, nerves can take years to repair, I honestly didn't think my hearing would ever sort itself out and the more I read on the internet about it the more fear was installed in me. I thought my life was over as I knew it and was very very depressed in an extremely dark place.
It takes time and lots of it, look after yourself, focus on the positive things in your life, keep active and give it time.