Warts, folliculitis, and acne are some of the causes of sideburns. 1. Warts: The abnormal growth of the skin caused by the infection of the human papilloma virus, which leads to the appearance of small bumps on the temples. 2. Folliculitis: Inflammation of the hair follicles caused by bacterial and other microbial infections, which can also lead to bumps. 3. Acne: In patients with acne, inflammation of the skin is caused by the exuberant secretion of the sebaceous glands and the infection of the bacteria Acinetobacter acnes, and the skin swells up and gives rise to the phenomenon of milia. There are many reasons for sideburn pimples, so it is recommended to go to the hospital for a clear diagnosis so as not to delay the condition.