SOLVED. YA twins, one drowns in pond when young [s]

[Rafi]

one drowns when they are quite young, and the other takes her dead sister's identity. The mother is an artist, there is something about the girl realizing that she isn't her sister from looking at her mother's painting.

Not Twins by Carolyn Cooney.

[Sallie]

"Haunted Sister" by Lael Littke
"By medical standards, sixteen-year-old Janine Palmer dies on the day of her automobile accident. When her spirit travels to the "other side," however, she is told that it isn't her time to die, and is sent back to live out her life. When she awakens from her coma, though, she discovers that she hasn't come back alone. There is someone else inside her mind. The voice in Janine's head claims to be the ghost of Lenore, Janine's twin sister, who drowned twelve years earlier. Lenore blames her own death on Janine and is determined to live again in her sister's body.

Now the two girls must vie for one body. Can Janine be sure that her twin is really inside her, or is she simply going crazy?"
https://www.goodreads.com/book/show/7...

[Rafi]

Yes, that's it, thanks!