Emo isn't about the look at all, it's started to be now but many are just posers, emo is an old music genre-an offshot of punk/post hardcore. But since some lazy reviewers have started calling pop-rock emo it's got worse.
Self expression features heavily and is a good thing to do esp. through art, poems and songs. The "Self-harm" can be for various reasons; a common one is distraction from emotional pain because for all physical pain emotionally it can be so much worse. Others, due to a fragile state of mind need to be reminded that the're still alive in a droning and all-to-painful world.
But if you really think it's about fashion (well the streo-typed fashion); i'm a guy with long blonde *curly* hair, not emo, i wear whatever i feel like and never vans etc., not emo, i hate streo-typed emo music,not emo.
So yeah, after all that i'm known as an emo, i don't label myself as due to stereo-types i am many things-none of which are emo.
Look around. Emos may not look how you look just accept society.