pinprick

[ pin-prik ]

/ ˈpɪnˌprɪk /

any minute puncture made by a pin or the like.

a negligible irritation or annoyance.

Origin of pinprick

First recorded in 1745–55; pin + prick

The gap between rhetoric and action was on vivid display this weekend with pinprick U.S. strikes in northern Iraq.

Obama's Iraq-Syria Dilemma: No Force Now on the Ground Can Beat ISIS |Jamie Dettmer |August 26, 2014 |DAILY BEAST
The offence itself seemed a pinprick beside the rankle of the wound to her pride.

Rest Harrow |Maurice Hewlett
Used as he had become, the past two years, to pinpricks of this sort, his colour betrayed how much the present pinprick hurt him.

The Brentons |Anna Chapin Ray
The cavalry horses and transport animals suffered from bursati, and even a pinprick expanded into a large open sore.

The River War |Winston S. Churchill

Besides, to shoot a mere amateur in Chouannerie would be as absurd as to fire on a balloon when a pinprick would disinflate it.

The Chouans |Honore de Balzac
And now thou art boasting aloud over this pinprick, which harms me not at all.

Stories from the Iliad |H. L. Havell

pinprick

/ (ˈpɪnˌprɪk) /

a slight puncture made by or as if by a pin

a small irritation

(tr) to puncture with or as if with a pin