I would suggest that you discuss this with the prosecuting attorney in the county where this happened.
I must warn you that such a case would be a hard sell to a jury.
I would suggest you talk to a medical malpractice attorney.
However, I suspect you have already signed all your rights away to compensation for that accident.
On my first day of employment, someone in HR had them say I was no longer approved for hire because of my failure to disclose this.
I agree; you failed to disclose it.
The expungement did not relieve you of the responsibility to disclose.