Producing much venom is dangerous isn't it?

Yes. As you can see, the bees called Tracker Jackers are genetically engineered bees that sting out a lot venom if their nest or hive is disturbed then they'll really catch you! And a few tributes get stung by the tracker jackers and you can hallucinate and die a painful death.

Glimmer from district whatever gets killed by the tracker jackers and her body quickly becomes disfigured. Davis, if you need to know what disfigured means, here's the definition:

Disfigured means that whatever happens to your body, it'll become uglier than your original body used to be. Glimmer's body soon becomes disfigured because of the tracker jackers. If you don't die, you're lucky to still be alive. But if you don't survive, poor you!

otherwise, be angry at Cato because he didn't die like Glimmer.