Pretty good, you left out some cliche stuff that common CP  creatures have which is good. But the part about gaining a mouth only when enranged kind of reminded me of Slenderman for some reason, I guess because some fans say he does. But the mouth you described does sound creepy.

Heaven, I've read your story and I must say I am impressed by your originality. The character you've created is both beguilingly intriguing and mysteriously haunting; a combination seldom seen in modern Creepypasta characters. You're story, mainly a description of the Leech, had ever present in it a beautiful yet unmistakable style of writing reminiscent of both French and Italian prose. Unfortunately, as is commonplace with this style, some parts of the story are difficult for the American or Englishman to understand. I've taken the liberty of editing the text, converting it into cleaner, sleeker English whilst retaining your original work of art. I hope you'll find the rendition to be suitable to your tastes.

The Leech is a tall character, about six-feet in height. She is skinny, but not as skinny as Slenderman, she is indicated to be partially anorexic because you can see her ribs. When nearby, she will lull you into a false sense of security by making you ignore her presence. When I say this I mean she will make you act normally. When she senses you're oblivious to her, she follows you on all fours from behind quiety.

She will then reach for your head. Once she has your head, she will make a lesion on your scalp, making it bleed just enough to taste you. Then she will hold you softly, making you squat into a sitting position. Making you lean up against her, she laps up your blood.

You'll feel at peace near her. Her gentle heartbeat, the warmth of her body, the way she puts her arms around you in an "X" as she touches her knees; as she does this you'll feel day-dreamy, starting to drift off... forgetting everything that ails you. You'll see nothing but whiteness in your mind. The flood of bliss passionately soothes you. All of your fantasies become true as the aparition seduces you into nothingness. The peace lasts forever in this tranquility and you'll worry about no stressful thing.

However, it is robbed from you when she's done. You'll beg for more, urging you to stay by her side...

Okay, now that you know one of her abilities let's move on:

She isn't too strong...just past the strength of an average man. She is damaged easily when hit in her torso or eyes

As you see her from time to time you may notice that her eye color has changed slightly. No I don't mean red colored, rainbow, bloody, or black eyes. Just familiar eye colors like the kind humans have.

Her eyes are slightly bigger than a humans', just barely a few centimeters on the top and bottom. Her pupils are also so to match the eye sockets, but not overly huge.

She has a dirty, tan complexion, and a young look in the face. Though, she does have a long, white tuft of hair due to age.

She has no visible mouth or nose, normally. She does however "gain" a mouth when enraged. It appears as a net-like bottomless pit, not saggy. (Can you picture it?) She will will also emit a deep, throaty moaning sound.

She can run moderately fast. Fast enough to keep up with someone.

Thank you.

There was no need, at all, to use that kind of sarcasm. Please don't do that again.

what do you mean?

He was obviously being sarcastic in that first paragraph. >.> I thought that was uncalled for. I know I'm a pretty harsh critic, but being sarcastic doens't help and makes you look like you're degrading the author of the work you looked at.

I don't think that was sarcasm