For someone with an acne-prone scalp, what ingredients should I look for in a shampoo?

Dr Justin says it well. Treat the acne first. IF not its an absolute waste of time chasing after the scars when new ones keep appearing. More often than not, products can play a large part in acne. Stick to a few products but gel-based are preferred. I don't believe in "packages" for acne as everyone is different in acne types AND scar types. Sit down and discuss carefully with your doctor and don't sign packages etc IF you don't feel comfortable. understand your condition better and you would be able to make a wiser choice!

Thank you for your close-up photo. Yes, chemical peels can be used for active acne to reduce clogged pores and treat PIH (post-inflammatory hyperpigmentation). Glycolic acid and salicylic acid peels are the best chemical peels for active acne. They also help to fade PIH. Chemical peels which are better for PIH are Jessner's peel. This is a chemical peel that combines several types of acids to lighten pigmentation. Expected cost of each chemical peel: range from $150 upwards. Minimum number of sessions: 3-5 sessions. Hope that this helps!