I've had tinnitus for thirty years, and it was sudden. I think it was after I was hit in the head with a basketball across a court, but anyone who knows anything about tinnitus says no, no way. Probably a coincidence. Anyway, there are possible fixes described in recent research, unlikely for me since I'm older.
Are you under the care of an ENT specialist? If not, please try to be seen by one of those, possibly at a university type hospital, privately or in a clinic.
In my case, and I presume others, the audiologists who tested me could hear the sound in my ears, or so they said. Please go to a place with experts.