Is it possible to say Lashon Hara against yourself? If "yes", where is the line between humility and Lashon Hara?

The "Chafetz Chaim" book says that one should not say Lashon Hara on one's self. He brought a story about himself that once he said Lashon Hara about himself and recieved a few blows for it. Humility hasn't to do with one speaking ill about himself, but with one considering himself void in relation to Hashem. Rabbi Chaim Katz