Froy is right. its a sink there.
1: Is unused paper and need to be a sink, so that u can see the jaw thats hidden under..
2: this is the Jaw
Here u can see the cp area collapsed.
Like Froy sayed u need to open up the model to do this sink, u need to reverse all the folds inside the square i made here on this pic. this can be hard if u dont have any clue on how to to it.
see this video:
http://www.youtube.com/watch?v=7-gb-K-cBu8
This is my fold..