Wish I could help you wityh that, but my hearing loss was minor at first, barely noticeable, but came on strongly in the LAST 2-3 Years.
I clearly remember when the first loss occurred. I was a young soldier (tanker) an done day I was dismounted and standing between the main gun tube muzzles of two tanks..when they both fired at once. Took my hat off, and removed the hearing of high pitched sounds, such as those old, squeaky alarm watches...never could hear those.
Unlike a shotgun, there was great pressure involved there, since the blast deflectors direct much of the blast to either side. I tend to blame the blast more than the sound.
I went to youtube to find a blast deflector, and came upon this video. The tank shown is a WW2 M4 Sherman 76mm gun tube. I was at Ft Knox, KY, ....training in the M47 Patton tank w/90mm gun tube. I wasn't as close as that refrigerator, but about half way between two that were about 20 yards apart. I doubt your shotgun would come up with that much blast.. Actual demo starts at about the 6 min mark.
https://www.youtube.com/watch?v=FxHwGrz9uKI