This is common in places schools and work. The authority figures. Will look at who is doing well or honest and will lean on them and rely on them for the truth. ( my teachers used to come to me with questions about the classes behavior when subs were there. you.re not alone in this) As they cant be everywhere all the time. They look for people that are observant and will be able to explain situations as they happen.
The main people that these girls are really hurting is themselves. As even though you may have brought it to light, ( or think you are the one that did). They are, and always will reap in the repercussions and results of their behavior. They can't learn lesson and succeed in lives on someones else scores and coat tails. Stand your ground. You are in the right here. You dont need to lie , just know that you have people around you that appreciate you, and look up to you.
Hold your friends close to you, keep those that want to cause you harm , at arms length but within your views and prayers as to know where they are.
If they think that trying to hurt you will change their situation then they are the ones that will lose , As they arent trying to reach their fullest potentials.
You just keep your own education and effort in the right directions. Do keep in mind that there will always be people that get upset, or will try to retaliate against those they feel jealous or angry at, because they see things in others they refuse to seek out in themselves.
This will bite them in their back sides sooner than later. Both my siblings , "though smart and had high grades", quit school and never went back. The dumbest thing that can happen is turning away the chances to learn. My sister realized that too late. It carried over unto her kids as they thought it was ok because their mother did it. Now they can't get where they want to , until they take the GED and go into trade school etc. to get the the place of learning again. My borther turned out bitter and rude and lazy.
This is the path kids like those girls are taking, and wont see until it's too late. They seek out things the wrong way. Through boys, ( that isnt to say boys are bad) or other things that arent good.
Though you feel bad now you will get past it, just focus on the friends you have now... and know the adults around you want to be there for you as you are there for them.