She had a large carbuncle on her back that was so painful it kept her awake at night.

carbuncle 是名词，指"痈"或"疖子"，这是一种皮肤感染，通常由细菌引起，表现为红肿、疼痛的肿块。这个词来自拉丁语 carbunculus（小煤炭），因为这种感染的部位常呈现暗红色，看起来像烧红的煤炭。