Well I walked out of school today to find my tire with what looks like a cut. Someone had taken a knife and sliced into the tred a little bit. They also took the little cap off of where the pressure gauge goes...I really don't know what thats called. The tire doesn't seem to have any like deep cuts. Should I be worried? What should I do?

The little cap is no big deal. You can gt them for free at a tire shop or 4 for 99 cents at Walmart.

The cut in the tire might be a problem, have it checked at a tire shop.

that "little thingy" is called a valve stem. good luck