My mom has had a "little sore" that would come and go on the top of her ear for many years. Now that she is in bed a lot it is constant and I have come to realize that this is a pressure sore. I am at a loss how to stop it, I've tried placing a doughnut shaped foam cushion under her head but if she moves just a fraction her ear is no longer in the hole, and she doesn't like lying on her other side for long.
I would get it checked out though as Jessie suggests before trying anything else.
Did some quick checking and found a whole list of ear skin issues at NIH:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2267455/. It's long, but comprehensive.
I'm wondering if some cotton fixed with the light medical tape applied at night might help? I'd still get it checked out though.
But your post is a good reminder to pay attention to ear skin.