My somewhat dodgy attempt at a horror story - I think it starts off ok, but the ending is weak. Any ideas?

The pain started in her lower left gum, right up the back where her wisdom tooth had never emerged. She used to joke about it sometimes, this lack of wisdom. No one laughed, it wasn’t really that kind of joke. The pain gave her hope for a while – perhaps that longed-for wisdom was finally arriving. But it faded after a few days.

The pain next emerged in the hinge of her jaw. It ached and seemed stiff, and sometimes as she chewed there was a clicking sound, as if her jaw was popping in and out of its socket. While out to dinner some friends commented on it. Did she always make that sound as she chewed?
Random pains started emerging all around her body. One day a wrist, another an ankle. Once there was a very specific sensation in the middle of her right bicep – it felt as if someone were giving her a slow injection into the muscle, pushing the needle in with exquisite control, millimeter by millimeter. She saw the doctor, who made a crack about belated growing pains and suggested she take anti-inflammitories. They didn’t help, and gave her stomach-ache into the bargain. By the end of summer she’d just got used to it. The pains, though annoying, were never very bad. She learned to ignore them and get on with her life.

That autumn she got a promotion. It meant more money and more responsibility. She now had the opportunity to put some of her ideas into practice. They met with some success and her reputation within the company grew. But she had less time to see Eric, her partner, less time with friends. And certainly no time to worry about the odd aches and pains.

A rash appeared on her thighs. It spread to her buttocks. Small, slightly raised points of redness marred her skin. It was embarrassing. Luckily she was working so late that Eric was generally asleep by the time she got home. She wouldn’t want him seeing her like this. She wouldn’t want to kiss him, either – her mouth was full of ulcers.

He was away the night she lay awake picking at one. It was large, and painful, and sat right inside the crease between the inside of her cheek and the roots of her teeth. Picking at it with her tongue hurt, and was probably making it worse. But there was something there, some protuberance that was annoying her. So she picked – she couldn’t help herself.

The thing, the annoyance, was numb. It was probably some tissue that had been killed off by the germs causing the ulcers. She got it between her teeth and bit down. But the texture was wrong, totally unlike dead mouth tissue. It was tough and fibrous, almost woody. She couldn’t bite all the way through. She tried with her fingers, but she couldn’t grasp it. It was too short, too wet. The tweezers in the bathroom were a better bet. With them she could grasp it, and did. She pulled. By now she was used to pain, and anyway, this was like picking a scab or squeezing a pimple – painful, but also deeply satisfying. Anyway, the scraping, sliding feeling of it wasn’t all that different from taking out her contact lenses.

It wouldn’t come all the way. Once she had a length of it she snipped it off with a pair of scissors. She stared at the pale, stiff thing, like a toughened piece of string. A word formed in her mind, only to be rejected. There was no way such a thing could be in her gum. She ignored the thought an went back to bed.

The next morning there was another ulcer on her tongue. Something was sticking out of this, too. She took out her tweezers and pulled. This was trickier, it seemed to catch inside and didn’t want to come. There was some blood. But she finally got it out – a network of fine fibres, smeared with red. There was something inside her, some illness or infection violating her internal spaces. She turned the shower to the hottest she could bear, ready to scrub hard, and undressed.

Her pyjamas caught slightly on the rash on her thighs as she pulled them off. The rash that had been red was now tinged with green. A field of small green bumps and spines peered from the skin on her thighs. She rubbed her hands over them and was met with a sensation like running her hands over not-too-recently shaved legs. She pulled at one of the larger objects. Green blades, enclosed within one another topped a small, delicate network of pale, blood smeared fibres . She could no longer deny what it was. Blood beaded at the hole in her leg, and inched its way downwards. She took out her tweezers again and sat on the bathroom floor, the shower forgotten. Blood pooled beneath her as she plucked the grass, blade by blade, out of her legs.