I too have Tinnitus and have had it for years long before getting back on bikes. It does not go away. After a while you just don't notice it any more. I wear ear plugs all the time now, it is something I should have paid more attention to when I was younger. Anything loud will cause Tinnitus, machinery, shop tools, loud music, wind, etc. From what my Doc says there is not much that can be done for it. Damage is done. But wearing ear plugs in loud situation does help prevent it getting worse.
I do not have high blood pressure and do not take aspirin products. Although what I have noticed that brings it on are large amounts of caffeine or when someone mentions that they have Tinnitus. I fact as I write this blurb the ringing started.