Can I use purifying salicylic acid and benzoyl peroxide together? Purifying salicylic acid to clean pores and benzoyl peroxide to kill bacteria.

Acne combo treatment. Yes, it is okay to use these two agents together for severe acne, but the combination can be too harsh for some people. It safest to start with a wash (cleansing soap) to test tolerance. If no severe redness or irritation, you can use topicals (pads or gels) one after the other.
Yes, you can. Acne is commonly treated with multiple medicated products such as these. Most people tolerate it well. Redness and irritation is a potential problem, which is usually improved by using a hypoallergenic moisturizer, using the products less frequently, or stopping one of them completely.