[Harry]

Nope, there is no way to get another one now. I still think they should have a repeat quest available for people who do it accidentally. D:

I agree,i dont think you can get another one.And i am kinda sure there is no repeat to get it again.But yeah it will be so nice if OS can put an repeat about those Dungeons keys,so there is a chance to get them again if accidentally something happen.