Ellie was in a bad place.
An absent father, a vacant mother who cared more about her next drink than her only daughter and an ex in love with someone else.
She'd ruined her one true shot at her perfect job, her chance at happiness, the only thing that truly mattered to her was now Paige "why is my head so light?" Michalcuck's.
Cutting seemed her only 'option', her only way of relieving her pain, perhaps at some form of happiness.
Besides, it was just .Cut, it's not like anyone actually cared about her, did it even matter?