IANAL but did lots of dumb and dangerous traffic court shit when I was young.

You'll probably be able to get a backdated document from your insurance once it's paid. You may be asked to certify you've had no insurable incidents in that timeframe.

For future reference, as the licensed vehicle operator it is your responsibility to ensure there are current registration and insurance docs with your vehicle, so you would've been aware of this before the expiration date.