The term 'It'll Curl Your Hair' is a phrase used to describe something that is very surprising or shocking. The crossword solutions for this term are PERM (4 letters) and IRON (4 letters). A perm is a chemical treatment used to curl hair, while an IRON is a tool used to straighten hair. Both of these treatments can be used to alter the appearance of hair, but they have opposite effects. Therefore, the phrase 'It'll Curl Your Hair' is used to describe something that is unexpected or shocking.