That afternoon, Dorian receives a letter from Lord Henry, but he sets it aside without opening it.
Later, Dorian wonders if his portrait has really changed like he thought. Surely not, he thinks of the portrait, hidden behind a screen. Finally, when he builds up his courage and looks at the portrait, he sees that the portrait has changed, just as he remembered. He speculates on the cause, fearing a "terrible reason."
The altered portrait forces Dorian to acknowledge his cruelty to Sibyl Vane. It is a "symbol of the degradation of sin" and will serve as his guide, his conscience. He composes a long letter to Sibyl in which he accuses himself of madness and begs her forgiveness. As he finishes writing the letter, Dorian feels absolved of his cruelty to Sibyl.
Lord Henry knocks on the library door and insists on speaking to Dorian. Lord Henry seems unusually consoling but advises Dorian not to dwell on the situation concerning Sibyl, which he explains is "dreadful" but not Dorian's fault. He asks Dorian questions about the previous night: Did Dorian meet Sibyl backstage? Was there a scene? He is pleased when Dorian says that he is not sorry for what happened.
Dorian, however, continues. He is not sorry because the matter has taught him a lesson. He tells Lord Henry of his plans to make amends and marry Sibyl.
Lord Henry, quite agitated, interrupts and asks if Dorian received his letter. Dorian admits that the letter did arrive but that he has not opened it. Lord Henry then tells Dorian the contents of his letter: Sibyl Vane is dead.
