Acupuncture-Like Transcutaneous Electrical Nerve Stimulation (ALTENS) or Pilocarpine in Treating Early Dry Mouth in Patients Undergoing Radiation Therapy for Head and Neck Cancer

head and neck cancer, xerostomia, hypopharyngeal cancer, laryngeal cancer, lip and oral cavity cancer, nasopharyngeal cancer, paranasal sinus and nasal cavity cancer, oropharyngeal cancer, salivary gland cancer, metastatic squamous neck cancer with occult primary, tongue cancer, interventional