Don't have time to read through the entire thread properly (I'm sure there's going to be some debate) but with most cases of hyperacusis, time seems to be the best healer. Of course there are exceptions but from my own experience, and having followed other members on this and other forums, it seems that hyperacusis can go away with time.
I had severe hyperacusis from the middle of 2013 through to the end of 2015 or beginning of 2016 - it's a bit hard to pinpoint when the symptoms actually subsided completely.
Anyway, when my hyperacusis was at it's worst I had the following symptoms: hearing distortion, extreme sensitivity to certain frequencies in both ears, tonic tenson tympani syndrome, feeling of fullness in my ears, almost constant pain in my left ear that would radiate through the left side of my face alongside my jaw and down into my shoulder, and just no tolerance for everyday normal noise. Exposure to loud noise would spike all my symptoms.
I resigned myself to the idea that it was going to be permanent and was super bummed, but I tried to stay positive and spent some time on here trying to be helpful to others going through similar situations.
Anyway, over time my ears just became less sensitive to noise and now the hyperacusis is completely gone. Tinnitus is still kicking but much more tolerable and stable. It was a roller coaster on my way to recovery though, I'd have periods early on where it seemed like my symptoms improved and then something would set me back and I'd be a mess for weeks, then the same sort of pattern seemed to repeat over and over. Over time the symptoms just stopped.
I can't pinpoint anything that definitely helped with my recovery but I did make an effort to use my ear plugs appropriately, I always kept them in my pocket and popped them in when I thought I was somewhere too loud, but over time I also put a great effort to gradually exposing myself to louder noise to increase my tolerance. I also got big into exercise and always recommend it to anyone on here, I work out 4 to 5 days a week either running, lifting weights, hiking, etc. Was by far the biggest thing that helped me deal with stress and anxiety. I also did a couple courses of prednisolone when the hyperacusis was really bad, and that gave me a break of a few weeks from the pain - it was a godsend at the time. And I've always been big into supplements so I was using stuff like NAC, B12, Niacin, Melatonin, Magnesium, etc.
I could yap on for ages though but you seem to be relatively new to tinnitus and hyperacusis, so try not to stress too much. Time is an amazing healer.
That said, I do hope that there's a continued focus by those in the industry to focus on hyperacusis research.