I am so sorry are u sure its crack hes on? JMO my ex never scratched like that on crack. I mean he twitched and was freaky to look at but I dont remember that. I know with heroin u pick your skin and it makes u scratch alot its from the opiate that makes u itch like crazy. I know when I was taking alot of pill I would pick my face and was very itchy. Or meth also makes u pick yourself give u the crawlies under the skin. Just wondering dont mean to make u worry more but that sounds different than crack. Hopefully someone will be around soon who knows more than I do.