DO NOT EVER lie on an 8500-8 medical application.
If the feds detect a discrepancy, and determine it to be deliberate misrepresentation, you'll at best be invited to accept revocation of any and all certificates in return for the removal of the threat of federal felony charges and prison time.
A pardon or expungement does not make it a good idea to exclude information either, it will still be worse than frowned upon.
I know someone who this happened to and it was NOT pretty.