hi
you need to apply for a pardon - this link.
if that is granted, then you can file for the expunction of the matter
you apply for the full pardon. i would think with the reason for wanting it, you would have a fair shot of getting it - it costs nothing to apply. so nothing ventured nothing gained. if you dont get it - you can try to file for the expunction but it does require the pardon.
Lawyer
Handle criminal matters in both state and federal courts