Hello!
A big metal thing fell on another similarly sized metal object, and ever since, I've had high-pitched tinnitus. I hear it almost all the time, but it's not severe, and I've largely habituated to it over the years. However, it's become more noticeable now that I have a lot of free time. I made it worse once by ignoring the rule, "If it feels slightly too loud, it is," which kind of strained my hearing. Thankfully, it returned to normal after a long time, and I've been super vigilant since then.
Earplugs are a must in loud environments—no exceptions—and I always mix music at a low volume. I also use a treble filter on tracks when applicable, and I reduce a lot of treble when listening to music with headphones or in-ear monitors. This workaround has worked well for me.
I haven't tried any particular treatments. I know many people have it much worse than I do. I thought I could share some tips and tricks that have allowed me to continue playing and recording music. I've been through a few spikes, which were beyond scary, so if I can help someone by sharing my experience, I'm happy to do so. It's not groundbreaking advice, but who knows—it might help someone out there.