Background: Breast cancer–related lymphedema is a frequent and disabling condition that affects function, skin quality, and psychological well-being. Early identification of tissue alterations is essential to improve management and prevent chronic fibrosis. This study aimed to develop an integrated aesthetic-medicine check-up combining clinical assessment, instrumental skin evaluation, and high-resolution ultrasound to support early diagnosis, objective stratification, and personalized cosmetological recommendations. Methods: Fifteen women with unilateral upper-limb secondary lymphedema after mastectomy underwent a standardized protocol including clinical examination, palpatory assessment, skin-instrumental measurements (corneometry, sebometry, pH, transepidermal water loss), and high-resolution ultrasound of the dermo-epidermal complex and subcutis across 17 limb sectors. Ultrasound findings were classified into normal, fluid, sclerotic, or undifferentiated patterns and compared with clinical severity. Results: Ultrasound detected dermal and subcutaneous alterations even in subclinical stages, revealing increased thickness, fluid patterns, and fibrotic changes. All patients showed reduced hydration, low superficial lipids, and increased transepidermal water loss, suggesting impairment of the skin barrier. More advanced stages were associated with sclerotic or undifferentiated ultrasound patterns, while early stages presented mostly normal or fluid profiles. The integrated evaluation enabled tailored cosmetological prescriptions, which improved patients’ skin comfort and supported rehabilitative strategies. Conclusions: Combining high-resolution ultrasound with dermo-aesthetic assessment enhances diagnostic accuracy and provides objective criteria for stratifying lymphedema severity. Personalized cosmetological interventions, guided by instrumental data, may support early management and contribute to improved quality of life after breast cancer treatment. This integrated model is consistent with current multidisciplinary recommendations and may represent a valuable addition to oncologic rehabilitation pathways. Simple Summary: Lymphedema of the arm is a frequent and debilitating consequence for women who undergo breast cancer surgery. It can cause swelling, discomfort, changes in the skin, and a strong impact on quality of life and body image. This study presents a new integrated check-up that combines clinical examination, instrumental skin measurements, and high-resolution ultrasound to identify early signs of lymphedema and guide personalized cosmetic recommendations. Ultrasound can reveal tissue changes even before visible swelling appears, allowing timely interventions that may prevent the condition from worsening. By analyzing skin hydration, lipids, pH, and water loss, the check-up also helps to create individualized skin-care programs aimed at improving comfort and supporting the skin barrier. This approach highlights how combining medical and dermo-aesthetic evaluation can provide more complete care for women after breast cancer treatment.