So, the most important thing to do if you have scalp acne, is take a close look at your products. You want to make sure you're not using any leave in conditioners, and if you are, make sure you don't put them close to the scalp. Keep them on the ends of your hair.
You definitely don't want to use any products with mineral oil or cocoa butter. Those can clog the hair follicles, and lead to scalp acne. You also don't want to use anything like silicon, diamethicone, or cyclomethicone. These are often found in frizz reducing hair products, so you want to take a quick look and make sure that none of the products have any of those things. I find that about 90 percent of the time, scalp acne is caused by hair products.
Now, what happens if you eliminate all those and you still have scalp acne? You should definitely go to your dermatologist at that point, so that he or she can take a bacterial culture and make sure that you don't need oral antibiotics, or make sure you don't have another dermatological condition that mimics scalp acne.