In the rapidly evolving realm of digital communication, TikTok has emerged as a significant player, blending entertainment with social interaction and content creation. This study delves into the effects of TikTok usage on mental well-being, analyzing the roles of platform addiction, content exposure, social engagement, feedback nature, and stress perception. Data from 90 university students were examined using structural equation modeling, revealing that platform addiction and content exposure are closely linked to increased social engagement, but also to heightened stress perception, which adversely affects mental well-being. Importantly, the feedback nature on TikTok serves as a critical mediator, influencing users’ emotional and psychological states. These findings underscore the intricate balance digital platforms must navigate between enhancing social connectivity and safeguarding users’ mental health. The results have profound implications for researchers, developers, and mental health professionals, emphasizing the need for digital environments that support positive interactions and mental well-being.