My Wife Recently Became Worried Because She Feels Like Her

My wife recently became worried because she feels like her head bones/plates have shifted; she says that it's "sinking in". I do feel sort of a ridge going from about her hairline to the middle of her head. It doesn't feel extreme but it is definitely there. Neither of us have noticed it before, so she is pretty convinced it is new. What could be causing this and is it anything to worry about?