Mom caught me masturbating --- so much embarrassment..

So, last night I was in the phone with my boyfriend and I was playing with myself, I closed my door and before that I went to say goodnight to my mom. I guess she got up when I went to my room and she like forcefully pushed my door open and shouted "why is your door closed all of the way?" Because I don't normally have it closed, I usually have it pushed up because its hot. But when she asked, on impulse I said "because I'm cold."--- meanwhile we don't have working central air because it broke, and I had two fans on... what a dumb excuse 🤦🏽‍♀️ She didn't say anything, she just closed my door and went back into her room.
I'm so embarrassed and scared of what she might say, I haven't seen her all day because she's been at work, but she comes home in a few and I'm terrified to see her, let alone have a conversation with her. I'm not sexually active as of yet, but I have a feeling that she's not going to believe me when I tell her now... 
Pray for me or something, I don't know what to do... 🤦🏽‍♀️🤦🏽‍♀️😓 
Signed,
A horny teenager who made a really dumb mistake.. 
Edit: I'm 16 for those who are asking.