I was diagnosed with Osgood Slaughter's when I was 10 and the orthopedic doctor told me that just working through the pain would not make things any worse. He said naproxen (Aleve) before practice could help with the pain, but that was about all he could do for it. Icing after practice or during if it feels irritated can sometimes help and there are a few different braces on the market that say they work for Osgood's, but I've never personally tried any of them. Typically the pain will lessen when growth slows down. You could always see an orthopedic doctor and ask for his opinion. He might suggest a short break, a specific brace, icing technique, or brace for your particular situation.
Personally, I quit gymnastics nearly 7 years ago (not because of Osgood Slaughter) and still have the Osgood's lump on my knee and it can cause me some pain if I bump it on something or have to sit with my knee bent for too long, but nothing unbearable. Many gymnasts experience Osgood's and typically manage to work through it.