AI | Technology | Innovation | Inventions on Instagram: "Tattoos last because the ink is placed in the one layer of skin that doesn’t constantly shed. A tattoo needle deposits pigment into the dermis, the deeper, stable layer beneath the epidermis. Your epidermis renews and flakes off every few weeks, but the dermis holds its structure, so the pigment stays put instead of being carried away with normal skin turnover. Your immune system then locks it in. Macrophages rush in to “clean up” the fore