extend the extension

M.Mcluhan said " Clothing is an extension of skin."
We might say " Hair is also an extension of skin."
Scientifically, a composition of hair is almost the same as that of skin.
That is to say, hair extend itself naturally and at the same time, hair is the skin itself.
We have been changing hair style as an extension of skin to (re)define yourself.
Sometime we extend this extension of body by hair extension.
Where the hair is going to ?