<p>Sun tattoos, also referred to as patterned sunburn lines, have recently emerged as a visible consequence of uneven ultraviolet (UV) exposure, increasingly shared on social media platforms, particularly by adolescents and young adults. These patterns arise from partial photoprotection by clothing, accessories, or stickers and reflect acute UV-induced inflammation and DNA damage. Although often trivialized or aestheticized online, repeated sunburns contribute to cumulative photodamage, photoaging, pigmentary disorders, and increased risk of skin cancer. This commentary examines sun tattoo lines from a behavioral dermatology perspective, highlighting how digital trends and social reinforcement may influence sun-exposure behaviors. Beyond their biomedical significance, these conspicuous lesions carry psychosocial implications and offer an opportunity for therapeutic intervention through patient education. We discuss the clinical relevance of recognizing sun tattoo lines as markers of risky UV behavior and propose their use as practical visual tools to reinforce photoprotection strategies in routine dermatologic care. Addressing such emerging behaviors requires integrating clinical prevention, patient counseling, and targeted public health communication within contemporary dermatology practice.</p>