Tinnitus

You can mentally turn it down and forget it'
This phenomenon is just as real for people who dwell upon it and magnify the noise.
I know drugs exist to help but I have no experience with them.
So turn it down or off
however it can return when reminded of it. NPR did a story on it and blasted the frequencies associated with the ringing, it all came back and took a good month to get rid of it. Now just reading about it has made it return.

Picture a volume knob that takes about a hundred turns to diminish the ringing until manageable. Repeat as needed.

Explosions can be a common cause but so can concert speakers.
Avoid 100 decibels and do not overcompensate with other volume knobs
Take headphones to the movies - do not pug them in, they are for protection only.