"
Cause they don't even know you
All they see is scars
They don't see the angel
Living in your heart
This line refers to people not being able to see past the scars, either literal scars and/or disfigurations, or metaphorical scars, or the bad things someone has done. Regardless of which kind of scars, it refers to the fact that the people can't see past it and see who they are on the inside, what kind of person they are.