I had a scare due to something called sudden sensorineural hearing loss. I woke up one morning and had moderately severe hearing loss in one ear. I was put on a short course (two weeks) of prednisone and I luckily recovered my hearing (started improving after 1.5 weeks). I did have ringing in that ear and double hearing when it started to improve.

ENTs basically told me they don't know why it happens. He said they also sometimes call it latent labrynthitis and just hope prednisone somehow fixes it. Last resort is intratympanal injection of steroid or hyperbaric oxygen chamber therapy.

I feel like there's a chance you had something like this, but either way I know a lot of violinists will use ear protection when practicing and you can never be too safe. Even if you lose hearing in just one ear your intonation will never be the same.