There has been a lot posted about this problem, not least of all from me. It is very tedious but most days I don't even think about it anymore.
Mine is fairly high frequency and leaves the vocal range largely in tact, though the top frequencies were largely lost to me. CAA did not seem to care about it.
25 years (from doing a lot of training on turbo props) till now, and have not heard of a real cure. I made a electromagnetic device and tried hitting the inner ear with these fields - at all sorts of listed frequencies, the idea is that it lifts the ‘hairs' of the high end frequencies that have been caused to lie flat and generate spurious signals. Not the slightest help.