Hi Ann-Marie,
If you go to surf shop you can usually find a wonderful array of beanies (I find surf shop beanies are not itchy), even though I have not even had my mastectomy yet (that is this tuesday) I have shaved my head a couple of times in the last 10 years (the last time being about 6 weeks ago well before my lumps were found and getting my diognosis, I shaved my head to annoy my store manager, yes childish but the look on his face was priceless), well anyway some beanies now days button up under the chin so they don't fall off while you sleep, i have slept in a beanie in wintertime for too many years to remember and it has never impacted on a good nights sleep. I got a Roxy beanie this year that is satin inside, with fur around the ears and forehead, a thick cotton on the outside and can button up under the chin, it is sooooo comfy to sleep in. The style code on the tag is :IRLCP124 (just in case you wish to have a look for one). Take care
Kim