Hi everyone, registered to ask for help

I lost a key. Not like I can't find it but that I completed all 12 quests and received all 12 keys. However, due to my clumsiness I accidentally tossed it out of my inventory.

I wanted to go back to redo the quest to get the key again but I already completed it. I tried logging out of the game completely, getting out of the Afterland area-then going back in. Not sure what else I can do.

Help would be much appreciated.

Thanks.