The Poison Spitter

I know you know her. 
She, who on the stillest nights, lurks in sleepless corners with acrid breath and acid tongue.
 A vile one, earless, for hers is a monologue. The whisperer of doubt and vicious reprimands.
 You may cover your ears and squeeze shut your eyes, but her slow poison has entered and drips, drips, drips down to your core.