I'm surprised so few people talk about banana peels on this forum. I first heard that it works to relieve mosquito bites, then after some more research I learned that people use it on pimples as well.
I have no idea if this would work on regular whitehead pimples, but I tried it on three cystic breakouts, one of which was rather large, and within fifteen minutes all were smaller, less inflamed, and hurt much less to the touch. I just cut squares of peel off and pressed it on the affected areas. Some people tape them on but I didn't find it a hassle to just hold it there with my hand.
I'm not a huge proponent of natural remedies since I've put basically every type of food on my face including lemon juice, strawberries, honey, baking soda, salt, pomegranates, eggs, cucumbers, aloe vera, etc etc and none have really provided stellar results. Banana peel has been the most effective for pimples.
Anyway I'm not really sure what the science is but I just know it worked for me. Wouldn't hurt to give it a try!