If the head of a tick breaks off and remains under the skin, it eventually disengages itself and falls off without further action. The head cannot transmit Lyme disease on its own, as the organisms that cause the illness are in the tick's stomach.
Removing a tick without leaving the head embedded requires a steady hand and patience. Tweezers are the best tool for the job. Gently grab the tick as close to the skin as possible. Avoid squeezing too hard. Pull upward slowly to encourage the insect to release its grip. Once the tick is removed, clean the wound thoroughly. If the head remains, clean the wound and allow the head to dislodge naturally.