I did something really dumb I assulted my sister

I am a 17-year-old male, and my sister is 19. It happened tonight around 2:00 AM. I was feeling very aroused, and I saw my sister sleeping in a way where her underwear was visible. I don't know what came over me, but it made me even more aroused. I got onto her bed and started masturbating. I touched her underwear with a quick tap so she wouldn't wake up, and I also tried licking it. After I ejaculated, immense guilt and disgust hit me. I don't know why I did that—I am not the kind of person who does things like that. Now I don't know what to do. I want to stop watching pornography and masturbating, and I am desperately hoping my sister was asleep and didn't realize what happened. I really need advice on what to do next

(Sorry for my English)