Good question...i am on tarceva 150mgs, sometime i think that it is circulation,my feeet get cold, and almost look blue,then it pases, with tarciva you are likely to get all kinds of nit picking thing nothing major just little stuff, but excessive eye sand for a week then it goes, sores in the nose,comes and goes, zits on the face, cracks in the feet, this is embarasing but the hinee crack gets really red and sore for a day or two, hands will just get red and be sore for a day or so, i wear gloves for most any work, and clear soaps ect. The skin issues wax and wane, all in all i call it sensitivity period, it does get better hope this helps you. God bless