pinprick

Jennifer WeinerのFly Away Homeを読んでいます。
When she couldn’t stall any longer she walked down the hallway and knocked on the door of Richard’s office. He was sitting behind his desk, in his good suit, one knee bouncing up and down. A pinprick of shaving cream clung to his jaw, and she found herself automatically reaching for a tissue before making herself stop. Maybe his girlfriend can wipe it off, she thought.
"pinprick" が気になるので辞書を見ます。
・Oxford English Dictionary: A cause of minor irritation: These explorations are, however, mere pinpricks in the impervious hide of western culture.
・Cambridge English Dictionary: something that is slightly annoying for a short time: You have to ignore the pinpricks and just get on with the job.
ピンが刺されば痛いし、蚊のような細いピンでも確かにイライラしますね。