I'm going to buy some Benadryl and maybe test it on a moderate day, so I'll know for sure if the tinnitus goes up or down.Benadryl does neither of these things.
If Benadryl is an anti-histamine and it works, then wouldn't taking quercetin be a better alternative for long-term use (with occasional breaks)? My vet recommended it for my dog who developed a mast cell tumor. MCTs are caused, or contributed to, by massive histamine release.
Excerpt: "Quercetin can also help stabilize the cells that release histamine in the body and thereby have an anti-inflammatory and antihistamine effect."
Edit to add: If Benadryl is useless, I'll try the scop patches.