Gore Is About Graphic And Violent Injuries (someone Having An Amputated Limb Isn't Gore, A Limb Being

Gore is about graphic and violent injuries (someone having an amputated limb isn't gore, a limb being violently cut off is), body horror is about unnatural or inhuman body features. Disabilities and illnesses, things that actual people have and live with, are neither unnatural nor inhuman.

A character vomiting up bloody flowers because they have hanahaki is body horror because hanahaki is fictional and flowers cannot actually grow in someone's lungs. A character vomiting up blood because they have a stomach tumor or another medical condition is not body horror because those are real medical issues that people experience. Appropriate trigger warnings or tags for that could include "blood", "emeto/emetophobia", or "medical" depending on what you feel needs to be warned for.