Papier mache in a mould

This shot shows half of a puppet head that has dried in situ in the mould. Note the border of papier mache overlapping out onto the mould body. This is deliberate, as the overlap gives you something to lever out the moulding once it is dry, without pulling or levering the moulding itself, and acts as a handle.
This means you are less likely to break it or distort it when you pull it out. The picture shows two modelling tools slid under ready to start levering out half of Judy's head.

Papier mache shrinks as it dries, and for this reason you should not pull the moulding out if it is not completely dry. If it is still wet and it dries out of the mould, it will distort.
Just because the overlap is dry, do not assume the whole moulding is. The overlap will almost always dry faster than the rest of the moulding, especially if it is a deep mould, or you have layered many layers in one go.