wow, dear, that's creepy... brrr... great job about the thrill, the detailed descriptions. I would like to come back more on the style as I am no native-speaker, but could find the one or the other edit improvement. Some are typos, I suppose.
Frankenstiens = I think you mean Frankensteins.
Letita = Letitia (third paragraph)
"Eighty - five percent. Rotten!"ejaculated the mother. = As I said, I'm no native speaker but have a good translation software. I suppose that "rotten" may not appropriate, if Stacy's mother should be a courteous lady - so the impression one has of her when she is introduced to the reader the first lines. More, the verb "ejaculate" sounds to me like "sperm splutter". That could do well in an intimate scenery. I suppose you mean "exclaim", or "proclaim".
and poor Stacy stared at an ugly bent woman = why poor? I would write "shy" or "uncertain". To me she is not "poor" but brave, because she wanted it, to go to the cottage.
positivley green = "positively"? what do you mean? "shiny" green, "pale" green?
Her right eyelid was covered with warts as well = this is a repetition; maybe a synonym would be more appropriate? like verruca or "purulent, hairy spots".
her tounge twisting around = "tongue", I suppose.
her few remaining teeth = another repetition; a synonyme could be "gnashers" (I found on www.leo.com)
many cakes lay on the table = "cake"-repetition could be completed, or changed by "pastries", "cookies", "biscuits", "soft pies"; table is more difficult. But maybe there are "tablets", "plates", "dishes" where the sweets are placed on.
sweets and cockroach = "candies", insects are not bad. What about "bugs", or "beetles"?
("earth worms" or "crawlers", brrrr)
The woman's head got separated from the body = I would write actively, "The woman's head separated from the body and landed on the floor"
Sally suddenly couldn't see clearly. = I would re-write it into "Sally's vision got suddenly blurred."
She was wading knee deep in BLOOD. = I would write in small capitals. The effect is more impressive than if you write it in big capital letters. Otherwise it notifies the reader "hey, here is something EXTREMELY IMPORTANT I have to tell YOU". :o)
and saw the haunting face of the woman rolled down = roll down
Mrs.Watson's porched = porch
coustume = costume
Her mother just wasn't pleased! = I think I did not catch the meaning of that sentence. What do you mean by that?
I really appreciated the turn in the end.
I hop I was not too controversial or critical with my comments. Your choice = you are the author. But whatever you do, go on writing!
Thanks for sharing!