"I'm just cold" can mean, "I'm depressed and I cut myself". "Cat scratches" can mean cutting. The arms aren't the only place, upper thighs and stomach can be chosen cutting spots because they are easier to hide.
This is why I hate society. They say things to you that can hurt but if or when you change it society finds a way to make it back fire. So screw society we have one life to live and in my opinion I'd rather live it my way.