You mean you don't know how to get back to the first part of the game? Or you don't know how to stop playing the Teemo game period? Is it that addicting, BR? IS IT?
If it's the first thing though, just click the Cho'gath picture when you're at the screen after you die.
"Cogito, ergo es eggo." A.K.A. "I think, therefore you are a waffle."