Nintendo Legend of Zelda: Majora's Mask 3D

Hey guys, so I have a couple questions for those of you have played through either the original N64 version of Majora's Mask, or the 3DS version.

I'm currently in the Woodfall Temple, and I'm stuck. I've cleansed the water in the temple and gotten the Boss Key, but I can't find the Boss Room... Is there something I'm missing thats screwing me up, or am I not doing something right?