My teacher touched me?!?

He told me to stay afterchool.. his room has noo windows and nobody saw. and he grabbed me and told me to not say anything or he would fail me! i was really scared and he fingered me! he tried to go further but i didnt let him! omg omg i cant believe this happen to me i cant tell my mom its too embarasiing! i want him to rot in jail omg should i tell the cops omg pls help me gimme good adivce i still cant believe this happened to me im crying. im going to 12th grade and btw im in summer school