I had a bad itch on my scalp and as I scratched it, I must have inadvertently scratched it too hard -- because now I have a small scab there! It made me realize that our scalp skin is so much different than the rest of our skin. I can scratch my arm five times harder than I scratched my scalp, and nothing would happen. What is so different about our scalps? (Mine shouldn't even be that sensitive, I have long hair and brush it a lot.)