Pustular acne on the back of the neck may be due to acne behind the neck. This acne may most commonly be pustular acne or cystic acne. In particular, cystic acne, if secondary infection occurs, may also produce localized pus symptoms. Most of this acne may be accompanied by localized redness and swelling, and in severe cases, may be accompanied by some pus overflow. If these pustular pimples occur singly, they may also be inflammatory reactions secondary to sebaceous cysts. Therefore, no matter which case it belongs to, it is related to infection. In this case, you need to go through active anti-infection treatment, and you can apply topical fusidic acid cream or mupirocin cream, etc. locally; then take oral antibiotics, such as oral doxycycline or memantin, etc.