How do I make a sculpture smooth!?

At school we are making puppets and i did mine a bit differently. I put clay over the paper mache and i'm trying to make it smooth then make it look like real skin and we can't leave the clay bare so does anyone know what to put on top of the clay to make it look like skin? I tried glad wrap but it doesn't stick on! The clay is skin color but I accidentally mixed blue with it so it has a bit of blue on it!