Well here's the thing, if you use tin to remove all feeling, you may end up losing all empathy towards people in pain, so Tin could make you okay with it, however, you'd be considered insane and dangerous.
Actually, that's a good character idea, someone who used tin to remove all pain and starts inflicting it and becomes terrified of pain and the end of his arc is getting all his metalminds removed and everything hurts him because he's so sensitive.