Mom Walked In

I was sitting at my PC watching porn and masturbating, I was getting close as I rubbed my clit, I was panting and sweating and my mom walked into my room to ask my something. I switched the pc screen fast before she was all the way in my room and she asked what I was doing so I lied and said listening to music but do you think she knows what I was doing? She asked what she had come to my room for after and then left but I felt like she could tell by me sweating and my face all red what I was actually doing.