I can feel your pain!!!! I lost hearing in my left ear 3 months ago and since then I have had constant ringing. Sometimes it is louder than other times. But, it is always there and always disgusting!!! When at the lower pitches, I try to treat the ringing like 'White Noise'. It helps as a distraction, but not a cure.
I am now going thru the testing stage of different CROS HA's because my right ear is fine. Fine except for the freakin ringing, ugh!!! The 1st pair didn't work for me and next week I'll try a different manufacturer.
I have read that Cochlear Implants can help to reduce the ringing. I hope things work out for you. Funny/Sad how modern medicine sometimes has zero explanations for human health problems!!!