Sister goes missing as a child, now an adult, she tries to find her after seeing her picture in a magazine

[Sarina]

Looking for a book about an adult female that travels back home with her sister and they reminisce about how their younger sister went missing when they were children. Then their mom thinks she sees a picture of the, now grown, girl in a magazine and she sets out to try to find this woman and find out what happened to her sister. I never finished the book and have lost it. Thanks!

[Kate]

When did you read this book?
Approximately when was it published?

[Juels]

How to Be Lost by Amanda Eyre Ward?

[Lobstergirl, au gratin]

Sarina, are you still looking for this or did you find it?