I feel for you.
Not the same as the FOID situation, but I got put on a hold for my first ever purchase. Took 5 days for Feds to get back with the NICS check, I was trying to purchase at a show, so dealer's home turf was way too far to travel.
Waited another month for my CCW approval sweating over what would show up and/or discount me. I was a dumb college kid myself
Layman's opinion - if the charge was dismissed, you should have no problem with appealing it, talk to your lawyer.
Good luck!