Can't Remember the Title of a Book?

The book was published in mid 90s -- it was a gothic horror/supernatural book -- I don't believe it was written by a major name author -- might have been a first novel. The book was about a family in the midwest with 2 children -- a boy and a girl. The family is poor and decide to garner some sympathy/money by having one of their children -- the boy (the older of the two children) -- fall down a well or a hole in the ground. However, the girl falls in instead -- the community gets her out, but she is forever changed by her experience. There is a lot of imagery with tree roots and the girl gets her mind warped by the experience and then, in later years, I believe she comes back for revenge.