This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Acne and chemical peeling, Subject name: Dental
Chemical peeling is indicated in all of the following except 
Select and explain. 
A. Acne vulgaris, B. Lichen planus, C. Melasma, D. Phtotoaging
B: Lichen planus
Answer: B: Lichen planus 
Explanation: Chemical peeling is indicated in Melasma, Acne, Acne scars and Photo ageing Chemical peels act by a. Skin resurfacing b. Collagen remodelling Thus they help is removal of scars/ pigmentation