Glint (The Plated Prisoner, #2) by Raven Kennedy

Glint follows a young woman named Olivia who has lived in isolation for years in a decaying castle. She possesses a mysterious power she cannot control - whenever she experiences strong emotions, precious stones and crystals form on her skin. When a clan of immortal warriors seeks out Olivia, she discovers her castle prison is no longer safe and is forced to flee. She joins the warriors on their quest to find a magical healing elixir, while also trying to hide her abilities. Along the way, she grapples with understanding her own power and forms a forbidden romance with one of the otherworldly warriors. Olivia must learn to wield her gift as she navigates secrets, enemies and her deepening relationship.