Acne vulgaris occurs when oil and dead skin cells clog pores, causing red, swollen blemishes. It most often affects teens due to rising hormone levels but can sometimes persist into adulthood. Home treatments include gentle washing, avoiding squeezing pimples, and using over-the-counter creams with salicylic acid, benzoyl peroxide, or tea tree oil to unclog pores and dry up blemishes. Preventing acne involves regular gentle washing and avoiding excessive sweating, oils, and sun exposure.