From the popular Linkin Park song. You use this when somebody is being an angsty bitch and generally whining about their lives and how they have it so much worse than you. See angst
"Ricky's whining about how his girlfriend left him. CRAWWWLING IN MY SKIIIIIN"
by Protodude August 29, 2004
Although the previous definitions may be right. The true meaning of the words comes from the feeling you get when your high on heroine and you feel as though you actually crawling in your on skin and your skin is moving and trying to come apart.
The I.V. drug has got me crawling in my skin.
by Mr. Manfreadi March 29, 2010