Middle Grade Sci Fi Book with a Twilight Zone like Plot

Sometime between 2006-2009 I read a book (middle grade chapter book) that was about a small town where everyone in the town had to get medication (I think it was a shot) on a regular basis. No one really talked about why they did it, it was just an accepted part of life and the kids of the town assume everyone does it. Something happenss to cause the main character (a boy) to miss his medication. I think something happens with one of his friends missing it first or starting to question why they have to get it. And without the medicine he grows thick white hair over either all of his body or his head and shoulders/uperback. I think he also grows much taller. And you find out that the town was not really human and the medicine was keeping them human looking. I think it was also implied that the adults in the town knew the truth. The cover might have had a picture of the character in his non human form on it.

The Dark Side of Nowhere by Neal Shusterman?

I think that’s it!