This sounds like the Mara Dyer trilogy (Mara not Maya) by Michelle Hodkin:
Mara cannot remember anything about the night her friends did. All she knows is what she’s been told: they went to an abandoned asylum, the building collapsed, and only Mara survived.
Two months later, Mara is eager to move forward with her life in a new town, but that’s easier said than done. A boy at school named Noah Shaw seems to know more about Mara’s tragic past than she does. And to make matters worse, Mara is beginning to see people and things that can’t possibly be there. Or can they?
When Mara goes searching for answers, she discovers a secret about herself that is most unbecoming. A secret that promises a future full of destruction, pain, love, evolution, and ultimately, retribution.
The first book, The Unbecoming of Mara Dyer, starts with Mara waking up in hospital after the building collapse that killed her friends and very nearly killed her.
The "J" you remember is Jude Lowe, who is the bad guy. He is believed to have been killed in the building collapse as well, but his remains could not be positive identified. I don't recall his arms being found in the debris though.
The teacher who has the anaphylactic shock in the Spanish teacher Christina Morales.
