Salicylic Acid is one of the most popular ingredients in skincare products used to treat acne. It is a BHA (Beta Hydroxy Acid), whose molecular structure allows it to penetrate deep into pores and clean out debris and other dead skin cells. This is extremely beneficial in preventing acne because acne is caused when excess oils and dirt clog up you pores. By cleaning our your pores, salicylic acid prevents these kinds of build ups that lead to acne.
If you're looking for a product with salicylic acid, The Ordinary has a very simple and affordable one: https://www.gofriendshop.com/products/the-ordinary-salicylic-acid-2-solution