Not the OC, but I’ve done something similar and it wasn’t permanent but it was effective short-term after listening. My idea was to match the pitch, turn up the volume until it was fairly loud, then shut off the sound, and when I did that the pitch was gone or greatly diminished for about a day.

Years...until a period of extreme stress came along. Came and went for a couple of years (along with a host of other stress induced fun) and now it's gone again.