Answer:
I have fangs and enjoy piecing holes with a single bite.
Although a human shape I wear, mother I never had. By every miss I'm valued much, still my cruel fate is such by boys I am often despised. What am I?
I can be in your body but never on your placemat. I'm always better when I'm fresh, but you'll never see me in the flesh. What am I?
I go inside boots and outside shoes.
There is one in a minute two in a moment and none in a thousand years. What is it?
No matter how little or how much you use me, you change me every month.