Diabetic foot ulcers reduce patient's quality of life and increase treatment costs, evaluating this condition is promising. We report the clinical progression of an elderly patient who developed a diabetic foot ulcer following minor trauma. She was treated for over 2 months until her condition progressed to Grade 4 on the Wagner Classification of Diabetic Foot. A Serial infrared thermography was performed. The treatment plan included antibiotics and a polylactic acid membrane until complete ulcer remission. Thermographic imaging showed a quantitative reduction of the temperature differences between the affected and contralateral foot from an initial ΔT: -4.6°C ± 2.4, progressing to ΔT: -1.7°C ± 1.6 at 12 weeks, and a temperature reduction from the proximal third tibial area with ΔT: -1.7°C ± 0.6, with a change to ΔT 0.8°C ± 0.4 at 12 weeks near the metatarsal bone region. This article underscores the use of infrared thermography to give physicians feedback on ulcer healing progression phases and treatment effectiveness.