What are some good ways to be more flexible and a better tumbler...!!!!! Explain? plz..?

So i have been a tumbler and cheerleader since i was 2. ive done competitive cheer and gymnastics. I used to be so flexible and had a double full standing and running, before i was nine.I was the skinny but tall flyer that had a scorpion extended and heelstretch past my head. I also had a scale that was completely straight. I could hold my leg up to my ear with out holding on. Also i had a chin chin. I quit for two years, then got back in to it last year. well, recently, i had a horrible back injury, due to tumbling and now i went back yesterday and i suck. i cant do anything like i used to please help.... now i am 12.. will turn thirteen in november. i want all my skills back and have worked my butt off for them.. any ways to hekp