I had been thinking about you quite a bit and hoping that you were able to get this perv arrested and out of your lives.
Thus, I'm glad that you did post back with an update. You've been given some great advice from SoulfulSurvivor and Seek2clean. I do hope that both you and your mom get some counseling so that you both can heal.
Always remember that your friend and his mom are good friends to you. He did the right thing by telling his mom and she did the right thing by calling the police.
If you find yourself having a hard time at school, don't hesitate to talk to your guidance counselor or a trusted teacher. They can intervene if anyone is making your life miserable.
And, yes, always remember that this was never your fault. If you do have to testify in court, stay brave. The courts have victim advocates who will be there to give you whatever support you need.
I wish you and your mom all the best as you both work to heal your wounds.