The horror writing is a literature genre that is not easy to get into. And sure, with the movies you can get an idea of what are you trying to make, but when that doesn't look too developed, you need a friendly hand.
What's the point of the horror genre? The situation you will describe, but it has to be very good to really scare people. And let's be honest, putting a lot of blood and guts is "just good" if you're making a movie; in a book, you have to be more meticulous, more precise, you need people getting really freaky when they read your work, and I can give a little help with that ride.
Since a kid, my background was composed by the horror literature, with Stephen King and Howard P. Lovecraft on top of it, also, I have knowledge of a very respectable amount of horror movies, and to capture them on paper is not a problem. I have made my own horror stories and they have proved to be good among people (I once won a contest with one of them, much to my surprise).
What can I offer?
You made a horror story, and you need an expert opinion, I read it and tell you what to add or what to change, but don't worry, the essence of what are you trying to make will be safe. I guarantee.