Why is heather half way coverd in shadow goo in drawn to life

I finished the 2nd one and it was so sad. She was in a car accident and damaged half of her face. Before you finish it she asks for her little brother and it shows you pictures of her life and its so sad. Her mom and dad died in it right there at the accident, but the brother lasted until he got to the hospital. She hugged him right when he died. i cant sleep now its that sad.