This story started out promising, but somewhere along the line it devolved into a weird combination of standard YA contrived romance and an attempt to gross out the reader.
Jenny begins as a sympathetic character, and her characterization and backstory are genuinely touching at times. In addition to her inability to touch others without hurting or killing them, she's the poor girl in a town where most of the people seem fairly well-off. Her father is a drunk and her mother, predictably, is dead. Jenny keeps her ability a secret, but when she discovers that bully Ashleigh's boyfriend Seth both has an ability and is immune to her "Jenny pox"... well... the story starts to fall apart.
Once the unconvincing romance between Jenny and Seth begins, Jenny's characterization starts to change. At first it seems like she's starting to stand up for herself, which is great, but eventually Jenny becomes a completely different character. By the end of the book, shy, gentle Jenny, who has taken great pains her entire life to avoid touching anyone so as not to harm them, takes her clothes off and grabs everyone she can get her hands on, killing nearly the entire town in a gory, pestilent rampage. Yes, the people were gathered by Ashleigh in her attempt to have Jenny and Seth killed by an angry mob, but most if not all of the people were innocent. Ashleigh herself shot Seth, not the townspeople. Ashleigh's influence had the town under a mass-hypnosis-like effect, and people under her influence were not in full control of their own actions. Jenny shows no regret or compassion for these people except when she spares the pregnant girls, an action that really didn't make any sense. She'd killed the rest of the town, why not them?
Just as I suspected the moment he died, Seth's healing ability brings him back to life, and he follows Jenny's tracks, pulls her out of the river she threw herself in to die (I do hope that the river was not a source of drinking water anywhere downstream...), and resurrects her. During the time they were dead, each of them magically 'remembered' their previous lives, in which they pretty much did the same things over and over. Infodump ex machina, yawn, and the story ends without the logical conclusion wherein the CDC comes in, quarantines the town, and the government hauls Jenny and Seth away for experimental research. And, oh yeah, mass murder. Yeesh.