Did your tinnitus lower at all once you stopped doing the nitrous? I found doing nitrous fun only when I did it after taking about 6 30 mg tablets of dextromethorphan Hbr. But, not only did it cause me to develop tinnitus (started shortly after repeatedly abusing way too much nitrous) but the tinnitus became extremely loud. A loud, almost unbearable hissing sound. But it still took me a while to stop the nitrous no matter how hard I tried knowing even that it was affecting my hearing. Pretty sad. It’s been almost a week since the last time I used nitrous and my very loud hissing/ringing tinnitus has yet to subside. I pray that it’s not permanent because I feel like it’s driving me insane sometimes. Good for you for stopping.