I have experienced what I believe to be tinnitus, on four or five occasions. Each time for long enough to understand what an awful the condition it is.
I have developed a simple method to help myself overcome it.
As soon as I begin to experience the condition (a high pitched ringing tone in either one of my ears): I apply myself to listening intently on the sound that I am experiencing as the problem. I do mean that I apply myself pin-pointedly on listening to the offending tone.
My tinnitus disappears.