Ringing ears (tinnitus) is not repairable. I have had it since 1985 when my brother in law and I went target shooting with a .380 and a .45. Definitely learned (the hard way) a lesson about hearing protection.
Unless you have pain or are bleeding my bet is your doctor wil have no suggestions for help with the noise. After a while, you don't really notice it much during the day, but at night it can drive you crazy. I have to sleep with a fan or a "white noise" machine or take Benadryl.....6 or 7 beers also helps.
Wish I had better news for you....maybe your damage wasn't as severe and it will clear up on its own.