I'm too-recently acquainted with riding bikes with discs to have anything first hand to share. Your plight reinforces my desire to proceed with due caution when the time comes for my brakes to need attention.

I did find this fairly new web article describing what happens when a brake lever is inadvertently applied without a disc being between the pads. There may be something in it that helps you get beyond what you're facing.

Other forum members with greater personal experience ought to be replying soon. I'm looking to learn from what they tell us as much as I'm hoping they help you solve your issue.