This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
A 56 years old man has painful rashes over his right upper eyelid and forehead for the last 48 hours. He underwent chemotherapy for Non-Hodgkin's lymphoma one year ago. His temperature is 98° F, blood pressure 138/76 mm Hg and pulse is 80/ minute. Examination shows no other abnormalities. Which of the following is the most likely diagnosis - 
Select and explain. 
A. Impetigo, B. Herpes zoster, C. Pyoderma gangrenosum, D. Erysipelas
B: Herpes zoster
Answer: B: Herpes zoster 
Explanation: None