Book about snake girl

[tokyoghoul504]

So these merchant people find a girl and she has snake skin on her stomach and so they cut it off or use magic to get rid of it. In the book she is like 18 and she can taste the air just like a snake. She is also about ti inherit some kind of merchant caravan or something. There is also these snake people who sacrifice people to this huge monster or huge serpent in a huge dark hole. I think the girl gets kidnapped later on by them. There is also a character who is i think a witch or something but nobody can remember unless she wants them to or shows herself but i think the girl can remember her or can always find her but i'm not entirely sure about that. I read this book maybe 4 years ago maybe more and i think on the cover she is on it with a forest behind her but im also not entirely sure about that either.