I think you are a: >! tooth! I live in a palace where it's dark inside No light in there, unless open wide >! Teeth live in mouths, which fit this description Even though I am not a king, sometimes I wear a crown >! Teeth sometimes have crowns I am not a queen either, neither I am a clown >! Obviously teeth are neither queens nor clowns, but I'm not sure if I'm missing a more specific connection here. I'm known for tearing stuff by moving up and down >! This describes chewing food Don't take care of me and I might hurt you >! If you don't brush and floss your teeth, they'll start to hurt! Take care of me and get better pictures of you >! People like to have a dazzling white smile for photos! Title: >! Without teeth, it would be harder to eat, which would definitely make life hard!