Because there are two kinds of clavicle hair: one is straight clavicle hair, which only needs to be cut into layers, which is very playful and age-reducing, and does not need to be permed.
Another kind of curly collarbone hair is more charming and gentle. Naturally, you need to use curly hair to perm and modify your face. So whether the clavicle hair needs ironing depends on which kind of clavicle hair you choose.