In this group, superficial needling (0.5-1 mm depth) was performed at non-meridian points located 1 cm lateral to: (1) primary local acupoints ST2 (Sibai), ST7 (Xiaguan), and ST4 (Dicang) on the affected side; (2) branch-specific supplementary points GB1 (Tongziliao) for ophthalmic branch involvement, SI18 (Quanliao) for maxillary branch involvement, and ST6 (Jiache) for mandibular branch involvement; and (3) bilateral distal points LI4 (Hegu) and TE5 (Waiguan). Local acupoint pairs (ST7 adjacent + GB1 adjacent, ST7 adjacent + SI18 adjacent, or ST7 adjacent + ST6 adjacent) and distal pairs (LI4 adjacent + TE5 adjacent) were connected to an electroacupuncture device. The electroacupuncture device was kept in the off state and did not generate any therapeutic current. The needles were retained for 60 minutes.Acupuncture treatment was administered for 5 consecutive days as one course, with a 2-day break between courses. A total of 2 courses were conducted.

CBZ placebo is a tablet with identical packaging and appearance to CBZ but lacks therapeutic effects. Patients were transitioned to a CBZ placebo at an equivalent daily dose post-enrollment. Orally administered for two consecutive weeks.

The primary acupoints selected were the affected side's Sibai (ST2), Xiaguan (ST7), and Dicang (ST4). Based on the affected nerve branch, additional acupoints were chosen: for the ophthalmic branch, Tongziliao (GB1); for the maxillary branch, Quanliao (SI18); and for the mandibular branch, Jiache (ST6). Distal acupoints included bilateral Hegu (LI4) and Waiguan (SJ5). Electroacupuncture was applied based on the affected nerve branch. For the ophthalmic branch, the local acupoints selected were Xiaguan + Tongziliao; for the maxillary branch, Xiaguan + Quanliao; and for the mandibular branch, Xiaguan + Jiache. The distal acupoints selected were Hegu + Waiguan. A sparse-dense wave, 2/100Hz, was used, with a treatment duration of 60 minutes. The intensity of the electrical current was adjusted according to the patient's tolerance. Acupuncture treatment is administered in 5 consecutive days as one course, with a 2-day break between courses. A total of 2 courses are conducted.

Patients will record the number of spontaneous and triggered paroxysmal pain episodes daily using a 24-hour pain diary. To capture the continuous trajectory of pain over the entire study period, the daily data will be aggregated and reported as weekly averages. The unit of measure is "Episodes per day".

Patients will rate their average pain intensity over the past 24 hours daily using a Visual Analog Scale (VAS) within the pain diary. The VAS ranges from 0 to 10, where higher scores indicate more severe pain. To capture the continuous trajectory, the daily scores will be aggregated and reported as weekly averages. The unit of measure is "Units on a scale".

Patients will rate their peak pain intensity over the past 24 hours daily using a Visual Analog Scale (VAS) within the pain diary. The VAS ranges from 0 to 10, where higher scores indicate worse pain. To capture the continuous trajectory, the daily scores will be aggregated and reported as weekly averages. The unit of measure is "Units on a scale".

The Patient Global Impression of Change (PGIC) scale is a patient-reported outcome measure used to dynamically monitor the trajectory of health status. This scale employs a seven-point Likert scale (1=very much worse to 7=very much better) to assess the impact of therapeutic interventions on an individual's functional status. Treatment efficacy is categorized into three levels: ① disease progression (scores 0-3) indicates a worsening of symptoms; ② functional stability (score 4) suggests no significant change in symptoms; and ③ clinical improvement (scores 5-7) represents a marked reduction in symptoms. This subjective assessment tool, through longitudinal comparison with baseline data, provides a direct reflection of the patient's perceived treatment benefit. The unit of measure is "Units on a scale".

The Short-Form McGill Pain Questionnaire (SF-MPQ) innovatively integrates qualitative and quantitative analyses of neuropathic pain. This involves: (1) Pain quality assessment: Utilizing 11 sensory descriptors (e.g., pricking, burning) and 4 affective descriptors (e.g., annoying, fearful), a 0-3 intensity rating system is established, synthesizing a Pain Rating Index (PRI = sensory score + affective score); (2) Pain intensity assessment: Employing a Visual Analog Scale (VAS) and the Present Pain Intensity index (PPI) for supplementary quantification. This scale significantly enhances clinical applicability while maintaining assessment validity, and has become a gold standard for neuropathic pain assessment. The Pain Rating Index (PRI) is calculated from the descriptors. The total PRI score ranges from 0 to 45. Higher total scores indicate worse neuropathic pain. The unit of measure is "Units on a scale".

The Brief Pain Inventory-Facial Scale (BPI-Facial) is designed to establish a three-dimensional assessment system: ① Pain intensity dimension (4 items) quantifies the frequency and severity of pain; ② Daily function dimension (7 items) assesses the impact of pain on basic life activities (including specific emotional states); ③ Facial function dimension (7 items) detects the degree of limitation in specific facial activities. Eighteen standardized items, measured from multiple perspectives, can systematically evaluate pain-related physiological, psychological, and social functional changes, providing multidimensional data support for efficacy determination. Each item is rated on a numerical scale from 0 to 10, yielding a total score that ranges from 0 to 180, where higher scores indicate more severe pain and greater functional impairment. The unit of measure is "Units on a scale".

In assessing anxiety via the Self-Rating Anxiety Scale (SAS), scoring yields two key metrics: the raw sum score (X) and the derived standard score (Y). The latter is calculated as the integer portion of 1.25X, with truncation applied. Per Chinese norms, a standard score (Y) of 50 serves as the threshold for clinical anxiety, with severity stratified as mild (50-59), moderate (60-69), or severe (≥70). The standard score ranges from 25 to 100. Higher scores represent more severe anxiety. The unit of measure is "Units on a scale".

The Self-Rating Depression Scale (SDS) is a brief, self-rated instrument for assessing depressive symptomatology. The total raw score (X) is derived by summing all item responses, which is then converted to a standard score (Y) by multiplying by 1.25 and truncating to an integer. Based on Chinese normative data, a standard score cutoff of 53 is adopted, with scores of 53-62, 63-72, and ≥73 indicating mild, moderate, and severe depression, respectively. The standard score ranges from 25 to 100. Higher scores reflect more severe depressive symptoms. The unit of measure is "Units on a scale".

Safety will be evaluated by monitoring the incidence of any adverse events during the study. These include acupuncture-related events (e.g., post-needling pain, subcutaneous hematoma), carbamazepine-related side effects (e.g., dizziness, nausea), and clinically significant laboratory abnormalities identified through Liver Function Tests (LFT) and Renal Function Tests (RFT). The outcome reports the total number of participants experiencing at least one adverse event. The unit of measure is "Number of participants".