You want to protect the brain, eyes and thyroid. That's why you don't Rife on the face. Never place TENS pads above the neckline at all. If you want to treat the head, place tens pads on the shoulders below the neckline. Often lower frequencies you will feel. Also if you are inadvertently tackling a pathogen, it will react making you feel the tingles more. It is also possible that the nerves and muscles are reacting to the lower frequencies. This is still safe though.
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