Clinical Evaluation of Dual-Plane Technique PN-Based Treatment for Horizontal Neck Lines Using DNA Fragment Opmizing Technology Polynucleotide (DOT PN)

The goal of this clinical study is to evaluate changes in the appearance of horizontal neck lines after treatment with DOT PN (Rejuran S), a polynucleotide-based injectable medical device, administered using a dual-plane injection technique in adults aged 25 to 65 years with mild to moderate horizontal neck lines. The main question it aims to answer is: \- What is the mean change in horizontal neck wrinkle depth from the start of the study (Week 0) to Week 16, as measured by 3D imaging? All participants will receive the same study treatment; there is no comparison group. Participants will: * Receive DOT PN injections in the neck (4.0 mL per session) every 4 weeks, for a total of 4 sessions (Weeks 0, 4, 8, and 12) * Attend 7 study visits over 24 weeks for 3D imaging, wrinkle grading, questionnaires, and safety checks The injection technique, including the use of a blunt-tip cannula for the deeper layer, is a study-specific procedure defined by the study protocol and standardized across all study sites.

Inclusion Criteria: In order to be eligible to participate in this study, an individual must meet all of the following criteria: * Voluntarily signs and dates the informed consent form (ICF) prior to any study-related procedures. * Male or female adults aged 25 to 65 years at the time of screening. * Presence of visible horizontal neck wrinkles, specifically graded as HNWS grade 1 to 3 (mild to moderate neck lines), confirmed on baseline imaging and clinical examination by the investigator. * Willingness and ability to comply with all study procedures, visit schedules, and photographic requirements for the duration of the study. Exclusion Criteria: * Prior Procedures. * Absolute Exclusion - History of any prior hyaluronic acid filler injection, or fat grafting in the neck area at any time in the past. * Temporary Exclusion - History of botulinum toxin or energy-based device (EBD) treatments (e.g., focused ultrasound, radiofrequency, lasers) in the neck area within 6 months prior to screening. * Female subjects who are pregnant or breastfeeding. * Presence of damaged skin (e.g., areas affected by inflammation or infection), active skin disease (e.g., contact derma s, eczema, psoriasis) or infection (bacterial, viral, fungal) in the treatment area. * History of allergic diseases, sarcoid granulomatous pathology, Osler's endocarditis, autoimmune disease (e.g., lupus, scleroderma, dermatomyosi s) or current use of immunosuppressive therapy. * Known hypersensitivity or allergy to the ingredients of the investigational device DOT PN (Rejuran S) * History of keloid forma on, or hypertrophic scarring. * Current use of anticoagulants (e.g., warfarin, heparin), an platelet agents (e.g., aspirin, clopidogrel), or NSAIDs that cannot be discon nued at least 7 days prior to injection, or a known history of bleeding disorders. * Any other condition that, in the opinion of the investigator, would make the subject unsuitable for the study or compromise the safety or validity of the study results.