Between Here and Forever, by Elizabeth Scott

Abby has spent her life living in the shadow of her popular and beautiful older sister.  When Tess is in a car accident and ends up in a coma, Abby finds herself spending her days at her bedside hoping to "wake up" her sister.  She even enlists the help of a boy named Eli to try to entice Tess out of unconsciousness.  But while outside observers could see Abby's actions as a sign of devotion (and perhaps a lack of acceptance), the truth is much harsher:  Abby needs Tess to wake up so that the family will return to normal and Abby will finally be able to escape the small town in which they live.

But when Abby's plan to use Eli goes awry and Abby discovers some hard truths about her "perfect" sister, the perfect world that Abby has created comes unglued.  And in the chaos that emerges, Abby discovers some truths about herself.

Well-written with strong character development.  It is a story well-told.  However, I'm not sure it was a story I necessarily was interested in.  Abby is a hard heroine to like.  While she certainly grows and expands her horizons throughout the story, she's so self-centered and clueless about other people, that it's hard to feel that her suffering is anything other than self-inflicted.  And it's harder still to feel much sympathy for her self-abuse.  By the thirtieth time she whines about how no one could ever love her, you really wanted to strangle her with an IV tube!