To evaluate the efficacy and safety of a serum product in improving facial SL/SK and post-inflammatory hyperpigmentation in adult females

INTERVENTION: NC group:The placebo was applied to the designated half of the face for 56 consecutive days.;intervention group:The product was applied to the designated half of the face for 56 consecutive days.; CONDITION: Solar Lentigo, Seborrheic Keratosis, Post‐inflammatory Hyperpigmentation PRIMARY OUTCOME: Improvement rate of objective facial symptoms; SECONDARY OUTCOME: Improvement rate of facial skin lightness L value;Improvement rate of facial skin melanin value;Improvement rate of facial transepidermal water loss (TEWL);Facial skin glossiness improvement rate;Improvement rate of facial skin color (yellow‐blue) b value;Improvement rate of facial skin individual typology angle (ITA°) value;Improvement rate of facial skin color (red‐green) a value; INCLUSION CRITERIA: 1. Sign the informed consent form, commit to complying with the study procedures, and cooperate throughout the entire research process; 2. Female Asian volunteers aged 18–55 years with sensitive skin; 3. Self‐assessed facial skin type as oily or combination oily, tolerant to acids, and screened as mild‐to‐moderate sensitive skin by the Hua Xi Questionnaire; 4. Self‐perceived skin issues such as roughness, dullness, or lack of radiance; 5. At least one spot (hyperpigmentation, SL/SK, or post‐inflammatory hyperpigmentation) larger than 3 mm in diameter on each side of the face, with an ITA° difference of no less than 10 between the spot and the adjacent non‐spot area; 6. Able to adhere to and use the assigned products as required during the study period; 7. Agree not to use any cosmetics, medications, or supplements that may affect the study outcomes during the trial; 8. For women of childbearing potential, must have practiced contraception for at