What you heard is likely a rare hearing disorder called Diplacusis or Polyacusis - aka hearing additional erroneous pitches: https://www.neilsperlingmd.com/blog/2018/05/everything-you-n...

I've had it in my right ear ever since being exposed to a loud engine for 9+ hours in 2021. It gets noticeable for loud sounds, especially in the 3700-5200hz range; in my right ear, I'll hear a high-pitched ringing overtone on top of whatever external I'm hearing. It's quite frustrating, but seems to come and go. Nice to hear that it faded over time for you - gives me hope!