This morning, I received acupuncture needles in my head (!!) and in my eyebrow (in addition to getting some needles in the not-nearly-as-cool back). I also needled my partner in the same places. Acupuncture is so cool. Receiving needles in these places DO NOT HURT, they just feel "odd", such as tingly, itchy, and/or warm. These signs are all normal; they signify that energy is being stimulated. They don't hurt because the needles do not penetrate any masses (i.e. they don't hit bones, nerves, or blood vessels) and they don't hit major pain receptors (nerves). They just penetrate the body in sensitive areas, meaning they just enter spots on the body where energy can be stimulated but no other structures (bone, vessels, and nerves) are disturbed in the process.
The eyebrow needled went subcutaneously, meaning it traveled under the skin, along the entire length of my eyebrow. The head needled also was inserted horizontally, under the skin, but above the skull and vasculature. If only I had taken a picture to show you all how cool it looked!