When an unexpected pimple emerges on your forehead, there can be many different causes. Our friends at MIMI [1] explain why a product in your shower could be the problem.

Teen Vogue [2] spoke with a dermatologist about the relationship between conditioner and acne, and it looks like the oily hair product might be a pimple-causing culprit.

"Products like conditioners can leave residue on the scalp and skin surface, clogging pores and triggering irritation," says Dr. Jessica Weiser, of New York Dermatology Group.

It makes total sense. We think adopting a routine of lathering on a coat of conditioner will remedy dry summer strands, but in reality, these oil-based products trap bacteria and create a breeding ground for acne, Weiser says. She says to apply a small amount (I tend to go overboard) and to steer clear of conditioners with jojoba and shea butter. Goodbye, my lovers.

It's also recommended to wash your face in the shower after shampooing and conditioning to prevent residue build-up. This will now be a vital part of my routine. I don't wash my hair every day, and I would add that conditioning less often also helps in this department.

Another rule of thumb that will take some time getting used to: don't apply conditioner within four inches of your scalp. If this step will keep acne [3] at bay, I'm all for it.

Check out more from MIMI:
This Is What Will Happen If You Pop Your Pimples [4]
The Best Face Wipes For Every Skin Type [5]
How Good Nutrition Can Fight Acne [6]