This movie tells the tale of a highly troubled teen who suffers from chronic hallucinations. Whether those hallucinations are the product of her traumatic past or a curse is not really clear. Apart from the fact that the protagonist has a hard time distinguishing reality from fantasy she also seems to suffer from agoraphobia (which is the clinical term for someone who is afraid of the outside world).
What really irked me about the movie were the totally random "2D dream sequences/daydreams" which if I had to guess were supposed to add some sort of artistic element. Kind of a given choice considering how the movie is about an artist but not quite solid in it's execution. It ended up being really silly. After all this is supposed to be a Horror movie and not a children's playbook.
Furthermore, the antagonist of the movie (the dark stranger) is basically an old man who is blackfacing/grayfacing. I know, this is supposed to be a scary movie but when I first saw the "dark stranger" I laughed out loud. It just seemed way too bizarre.
To conclude: Was the movie scary? No, not really.