I have a tumor high in the apex of my lung which I'm receiving radiation. I started sweating just on one side of my head. Also my right hand is always cold but not the left. My oncologist tested my eyes for Horner Syndrome and they were find. Does anyone know any other causes of this sweating. He is sending me to a neurologist, and I'm scared to death that the cancer has metastisized the brain. Anybody have any ideas?