pick at

verb3

1. •
   To touch, grab, handle, or pull tentatively or gingerly, using a utensil or one's fingers.

   • Mr Vholes remained immovable, except that he secretly picked at one of the red pimples on his yellow face with his black glove. — 1852
2. •
   Synonym of peck at.

   • Picking at a salad in a conference room at Google’s headquarters here, Ms. Mayer says she is vexed by how some perceive her. — 2009
3. •
   To pick on or repeatedly criticize (someone).

   • "[N]oise and disrespect of no kind ain't pleasin' to him. His own folks behave becomin', but strangers go and act as they like. . . . Then we are picked at for their doin's." — 1872