Decades ago I was exposed to large noises from explosions in Vietnam. The ringing in my ears continued for five years and then diminished and normal hearing returned. My experience is anecdotal, and the etiology of the damage I had and you have may not be the same, but I would not give up hope.
How are you?
Acoustic trauma can result in constant ringing in the ears. It is very likely that you have suffered that. I would suggest you to please get yourself evaluated by an ENT specialist as soon as possible.