Answer:
I am the only thing that place today before yesterday. (one word)
I touch the Earth, I touch the sky, but if I touch you, you’ll likely die. What am I?
An action done on mosquito bites
Tear me off and scratch my head what once red is now black.
I am the key that is the hardest to turn
It weighs next to nothing but no one can hold it for long. What is it?