A closer look
Decorating your temple sounds poetic until your immune system decides your new medical alert tattoo is a hostile invader. Red ink is notoriously rebellious, often containing cinnabar or cadmium. Your macrophages try to eat these heavy metals, fail miserably, and wall them off in angry, itchy nodules called granulomas. This delayed hypersensitivity reaction can suddenly erupt decades after the needle touched your skin, turning a helpful medical tattoo into a chronic dermatological nightmare.
