I am so glad to hear yours went down significantly - sure hope I have the same reaction, but I am still doubtful since I had an actual perforated ear drum while vaping and not just 'a ringing that came out of nowhere'.
Granted this MAY not even be the cause, but it sure as hell is if you ask me - like I said, seems pointless to even have my MRI on the 20th coming up, but may as well go through with it - I have an appointment after that with my ENT I will definitely mention the vape issue.
I haven't vaped in 3 days now since I found PG on the list. I don't really notice the T while I'm hitting some trails on my mountain bike or when I am very occupied (hands on stuff) - hardly hear it at work because I wear a headset in my good ear and I am constantly talking and hearing a voice in my ear.
Other then that, It's always present - it ranges from annoying to FOR FUCKS SAKE. Sometimes I can plug both my ears, and then keep my good ear plugged and that will provide a few moments of tear bringing silence.
As far as the hyperacusis goes, I think that may be what I hear. When any noise is present the whistle seems to be there, but not so much in dead silence. However it seems I've always had a dull ringing (in extreme silence) all my life, I never really knew it wasn't normal, I just kind of thought it was air molecules hitting your ear drum or something. When it is really silent, that 'dull ring' that I've always known as silence can drown out the high pitched whistle, or, a cicada more I guess.. dog whistle, etc - whatever it is - so thankfully sleep isn't an issue for me.
I will admit sometimes I notice myself not noticing it, but all that does is make you notice it.. such a vicious cruel cycle lol.
Just got out of work so my mind is still in go mode - forgive the rough format and babbling