I know this isn't much to go on but it is a very fleeting memory.
A group is being chased, they rest in a tree. The girl is telepathic (throughout the story she constantly chews her knuckles). She can read the minds of beings, and describes that when she reads minds, its like reading several thoughts at once. She reads the mind of some form of demon? and it's described like reading thousands of thoughts at once, she chews her knuckle to the bone, vomits and passes out. The group move on, but the vomit she leaves behind tells those who are chasing them where they are.
A group is being chased, they rest in a tree. The girl is telepathic (throughout the story she constantly chews her knuckles). She can read the minds of beings, and describes that when she reads minds, its like reading several thoughts at once. She reads the mind of some form of demon? and it's described like reading thousands of thoughts at once, she chews her knuckle to the bone, vomits and passes out. The group move on, but the vomit she leaves behind tells those who are chasing them where they are.