Tinnitus has many causes. Antibiotics can cause it, diseases, and loud sounds are the main reasons.
That stuff they advertise on TV...I've tried it and had NO success with it, and it's pretty expensive. It is now sold in Walgreens and other big chain drug stores.
Mine has been constant and pretty loud actually, since my late 20's when I played in some really loud bands. At night we played in excess of 120db and during the days we would often go shooting pistols. A .357 is really loud. Kinda wish I had used ear plugs all the time, especially with the guns, but it's too late now. I have been to a few MD's over the years and none said anything I didn't already know. they all said that short of some sort of miracle, I'd likely have it until I die. Once the inner ear cilia are damaged, they do not heal.
One band in particular...we ran an average of 118db on stage and during a drum solo the meter actually went to 122db average. In another short lived band, we were so loud that I could hear my ears shutting down in the first song..... like eq'ing out the highs. That band lasted a month or so before we broke up. I tried, as did the other guitar player, to use those fancy ear plugs but the tone didn't cut it.
Mine is a constant freq around 4k. I hear it all day long when I am awake. It gets worse when I am sick. I have simply learned to deal with it as a fact of life and i simply ignore it. I can turn the music up in my ear buds to about the same level and mask it pretty well. The biggest issue is understanding some speech and kids, and people who speak quietly. My wife is on me all the time about "I don't listen" ....I won't go into that any deeper here....
I just gotta play the cards now that I dealt for myself when I was in my 20's.