Through Torah study, the damage caused by lashon hara can be repaired to some extent.  The Gemara states (Arachin 15b): “How can speakers of lashon hara correct their deeds? If they are scholars, let them toil in Torah, as the verse says, ‘A healing for the tongue is the Tree of Life.’ (Mishelei 15:5). ~ The Chofetz Chaim zt”l