First and foremost, I want to say that I love this. I would rock this because I often wear quirky little accessories. The problem is that when women wear this, it's fun and cute - a little weird, but mostly fun and cute. If a guy wears this it looks like he likes to hunt and kill women. There's something off putting about a man with a doll head on his neck. Or a grown man who even owns a severed doll head.
I wonder if the girl's face looks like the doll. That's where this could get really cool. You'd wear a tiny version of your own face on your neck. People wouldn't know where to look when they were talking to you. You could always use the line, "my eyes are up here," or, "my eyes are down here."