Steel Key Reset (re-pop)

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I am currently on "The Blood of Kings: Find a Way Into Castle Langskaal" and need a Steel Key to open the gate.  I grabbed both steel keys (the one just north of that gate) and the one from the fairy puzzles during Into the Woods.  The problem is before I did "The Lost Rookery", I went back through old areas in search of gear to buy and found monsters had respawned which was good as I needed XP.  Well, I'm fairly sure I used a steel key in the Woods area the 2nd time through when a steel door was closed.  Now I am short 1 steel key.

Is there a way to reset the placement of these keys in the world so I can continue with having to restart the game?