Help?

My current boyfriend is 15, 2 years older than me. He’s super sweet, caring, and a genuinely nice person. Yesterday I had (Ik this is wrong don’t bash me for it pls) snuck him into my house because obviously my parents don’t know I have a boyfriend two years older. We were just watching tv in my room and chilling (my parents weren’t home yet) when I’m not really sure how it happened but I was tracing his thighs and the next thing you know I had pulled out his dick and began giving him a handjob. He was really close to cumming when my sister walked in to tell me to do the dishes. I had no clue she was even home bc usually she has a study group she meets with from 3-5. She’s for sure going to tell my mom and I don’t know what I’m going to do. I’m highkey scared.