What Causes Smoke Smell And Metallic Taste While Having Brain Stem Dysfunction?

Sorry, but i doubt if i can get a absolute correct answer on this one. from dec.1, 2010 to now (5-18-2011) i have a constant smoke smell and taste plus a metallic taste. I have Porphyria, Central Apnea from brain stem dysfunction and Asthma and about eight other conditions. The smoke smell and taste is so strong it makes me cough and i sense it in my eyes. I realize that sounds nutty, but that is the way it is. I wonder if my Bipap Auto SV set at 24/14/9 could have damaged my cranial nerves because i also get a sensation that my teeth are leeking a metallic taste. I have used a Bipap since 1991. The teeth are functionally fine and not diseased.