Hey I have osgoods. I feel your pain. Osgoods is horrible. I had bands on both my knees, and I went to phsyical therapy, but to tell you the truth it didn't do much good. Basically you just have to wait to stop growing. I took a year off which helped a little bit, but going back was still painful, you really have to suck up the pain. I would suggest icing before and after practice, try to give your knee a ton of rest outside of gym.
At gym, if possible do vault and floor last. Try to focus a lot on bars and beam. Really try not to run and jump (which I know is super hard in gymnastics) unless necessary. Keep vaulting to a minimum. To stay in shape work on tons of drills, and also do a lot of knee strenghtening and core excercising.
My bands have lasted me for 5 years, they were like 60 total but have been worth it. It goes right under the knee cap, and I got it from my sports doctor, so if you get some go to your sports doctor, they'll know the best type.
If you need any more help, just ask, I know how you feel and good luck!