Wearable electroceuticals are emerging as a key platform for health management due to their safety and non-invasiveness, with therapeutic efficacy enhanced by close skin contact. In this study, we present a wearable organic light-emitting diode (OLED) patch that integrates flexible hardware and a flexible battery for self-operation and reusability. The OLED exhibits excellent mechanical flexibility, adhering intimately to the skin while maintaining a safe temperature range of 20 °C at 5 mW/cm², stable operation for over 1000 h, and high moisture resistance. Daily irradiation with 632 nm OLED light (9 J/cm²) in mouse models of psoriasis and atopic dermatitis (AD) led to significant recovery of epidermal thickness and transepidermal water loss (TEWL) to near-normal levels. The expression of inflammatory cytokines (IL-4, IL-17, and IL-22) also tended to be suppressed. These results suggest that wearable OLED-based phototherapy can complement the limitations of existing treatments and offer a self-administered treatment strategy.