Answer:
I have a head and a tail but my eyes can never see my tail.
I turn around once. What is out will not get in. I turn around again. What is in will not get out.
I cut through evil like a double edged sword and chaos flees at my approach. Balance I single-handedly upraise through battles fought with heart and mind instead of with my gaze.
I fly away as soon as you set me loose. People around you may slowly move away once they sense my presence.
I can be sweet or sour. I do not rhyme with any other word
A man goes out in heavy rain with nothing to protect him from it. His hair doesn't get wet. How does he do that?