AMC: Did I miss something?

So just before the explosion...the "real" Erica was in the blue dress right? Then when Jackson found her, she was in the blue dress but it's the "other" Erica? Did I miss something that may have explained the outfit change? Or is this another miraculous moment in soaps? Or is the "other" Erica locked up now and the real one is really just messed up? I am confused!