So I’ve been searching for a book which I think was possibly a young adults book, or possibly made for young teens. I believe the book was historically set and involved vikings. The main character (possibly called Ingrid or Sigrid) was married to the Viking king (or someone high up in the Viking family). The main part I remember is that the people of the town disliked her, I believe she was good at making potions. There was a chapter when someone had tried to kill her husband by placing poison in his drink, but before he drank it she had a suspicion and rubbed some on her lip, making her lip swell.
Lost Classics of Teen Lit: Name That Book! 