No matter how many times you wash, scrub, or begrudgingly pop (eek!) that blackhead, which has so sweetly claimed real estate across your nose, it'll resurface weeks (maybe even days) later, as it if were an extra in The Walking Dead. What gives? Turns out, that zombie blemish isn't as uncommon as you'd think. "It is an interesting and common occurrence to have a pimple or blackhead pop up in the same spot," says Ava Shamban, a Los Angeles-based dermatologist. As for the cause of said alive-again blemish, well, experts aren't really sure — but they have some ideas. "One possible explanation is that there are a cluster of oil glands, or even a cluster of bacteria, that live in that location, which constantly cause inflammation," says Shamban. And for those blackheads that keep re-appearing on the nose? Shari Marchbein, a dermatologist and clinical assistant professor of dermatology at New York University School of Medicine, says they may not actu...