Answer:
Look into my face and I'm everybody. Scratch my back and I'm nobody.
Sometimes black, sometimes white, I have veins but no blood
What comes once in a minute, twice in a moment, but never in a thousand years?
We are few to the wise; We are abundant to the drunken; We can calm the beast and are precious to the child; We can devour the heart, without piercing the skin
What is eaten but not grown and was born in water but will disappear if soaked?
I have two eyes in the front and a lot of eyes on my tail