What Am I?

I've eyes and teeth but with no need,
My skin is tough and never bleeds,
I speak with words but not with tongue,
An empty chest that needs no lungs,
My smile's painted on my face,
My mind is but a hollow space,
I never grow but never shrink,
My eyes have not once had to blink,
I remain still until the need,
I'll entertain upon your knee