Bullying happens in this world all the time and it will also keep happening sadly. So besides yourself I am sure there are a lot of people who are in a similar situation like you are. You can either learn from it and grow stronger or you can give up. But as we have seen, giving up really doesn't give anything. Learning from it and growing stronger however, will show everyone what you've made of.
So what you have messed up teeth and someone is accusing you of bad things. I'm sure all the people who matter know the truth and those are the only people who's opinion should matter for you.
So in the nicest way, take your head out of your ass, stick your chest up and show those bully's you're not a little bitch. If the police didn't believe you since you looked like a drug addict then change the way you look. You don't need expensive clothes or teeth to be looked at as a "professional" in the sense who's story the police will believe.