How do you fake/escape from emotion?

I did something bad at school. I mean bad. The teachers dont know about this but I'm feeling increasingly guilty. My mom is very good at reading body language. In the past she found out something that happened nomatter how much I lied,. Is there anyway to completely hide from these bad feelings other than confessing what happened? this is a serious question. I dont want to hear about the so called RIGHT THING TO DO but I just want to be able to hide it so I dont get into serious s!@#t.