Got caught masturbating!! Plz help!!?

well i was in my bedroom, and no one else was in the house, and i was was watching this show...... that got me really............frisky........ so i decided to... u know....and i didnt here my moms car pull up, she walked in on me... i screamed and she looked so scared... i know you guys are going to say "should have locked your door!" and stuff like that...... but im not allowed to have a lock on my door cuz my mom and dad says i dont need one cuz i shouldnt need privacy since im 13..... im too scared to come out of my room and talk to her help me :(!!