My initial onset was noise induced. It got massively better by the 4-6 month mark. Went from an intense electrical hiss / tonal noises to mostly just a mild oscillating hiss that was far less bothersome. I could even make it disappear entirely for several minutes if I slept long enough, by that point.
I believe Misery, a poster here, also had intrusive tinnitus once for several months and it resolved completely.
I screwed up recently (med induced), and now my T is rather crappy again, but T does often get better for folks.