We have a few different lines that are great for treating acne for teens. I suggest using Clinique, The Body Shop Tea Tree Oil, or ClickR Skin Care which is a fantastic line that is specifically geared towards teens.
The best option would be to start with a set that gives you a bit of each product necessary to treat the skin: a cleanser, toner, moisturizer and treatment. I've included a few different sets that also carry the individual products. Any of these line would be great for a teen boy to use.
This set is great because it comes with a hot face mask, dermabrasion wash (to remove dead skin cells and buildup), a vanishing mist to purify and soothe the skin, and the acne face treatment which helps to treat and prevent breakouts.
A gentle yet effective treatment kit that comes with 3 super easy to use products: cleansing foam, a clarifying lotion, and the oil free clearing moisturizer all of which are allergy tested and fragrance free.
I love this set and use it myself because not only are the ingredients more natural but tea tree oil is a known antibacterial agent that helps to treat and prevent blemishes without overdrying them.
I hope my recommendations can help.