oh you have my sympathies!
it sounds miserable. I don't have any experience with Iressa but with if this might help...

Don't know if these products would be approppriate, but during radiation i first used off the shelf 100% aloe vera gel. It seemed to sooth the skin, but wasn't what I would call strong. Then I was given a tube of "RadiaGel" to apply to my sore skin. Its made by Carrington and is described as hydrogel wound dressing, a non-oily formulation for the radiation patient. Formulated for the management of radiation dermatitis and relief of pain." I liked it (I think its by prescription)

Also, for other skin itches/rash I've been given cortisone/hydrocortosone pills or injections, which have always helped.
good luck!
michelle

History of leukoplakia <2001-2004. SCC lateral tongue 9/03; left radical neck dissection & hemiglosectomy 10/03, T2-3,N0M0; 28 IMRT radiation completed 12/03. 30 HBO dives Oct-Nov 04 for infections and bone necrosis -mandible.