Just when you think you got it for good, it’s back. That smattering of acne always has a way of popping up again when you least expect it. Why oh why is clear skin so fleeting? Well, there are a few likely answers. Before you blame the products you invested in, keep reading—these common culprits may surprise you!

By now you understand that beautiful, glowing skin starts on the inside. It’s pretty simple: Put good in; get good out. You can slather your face with all the antioxidants, vitamins, and minerals you want, but if you’re filling up on processed food, all that junk eventually makes its way out through your pores. And it’s not just greasy, sugary foods; dairy is another culprit. It’s a pro-inflammatory that exacerbates acne and increases production of pore-clogging sebum. Byrdie: