My gut tells me to tell you to stop. Stop messing with your sinuses right now.
You need to step back. Reboot. Take all your symptoms one at a time.
I have the same problems. I left my sinuses and ears alone and started working on everything else. I cochlear damage, so I have learned to live with my ringing. I have really itchy ears, and all the things I put in them (H202, CS, herbs, iodine) made them worse.
But the rest of me feels great. I think the brain fog is from something else in your body. So are the headaches.
You are irritating you sinuses. Let them heal and reassess.
This is only my 2 cents. I hope you get well, because the whole thing sounds like it sucks.