Jerry fights back, but he finally gives up and says "I should have sold the chocolates. I played their game anyway." Did he actually lose?
Whether or not Jerry "won" is up to interpretation. In the most factual sense Jerry lost; he was beaten by the mob. Archie and The Vigils were too powerful to allow one boy, standing alone in defiance, to go unpunished. And Jerry was punished horribly, being brutally beaten in the ring by Emile. So his defiance, in the end, was met by no major change in The Vigils, and it resulted in Jerry's public humiliation and physical punishment.
But if you look at Jerry's defiance in another way, a kind of victory can be found. Jerry was brave enough to do something unthinkable to the other students: stand alone and defy The Vigils. Though other students (especially Jerry's friend Goober) were not able to have the kind of courage Jerry did, they were at least able to see that defiance to tyranny was possible. Also, Jerry had a major internal victory -- he didn't give in to the hypocritical chocolate sale, and kept his own self-respect intact. This, perhaps, is the most significant victory in the book. Jerry was able to see a right path which was different than everyone's around him. He took it, and stayed true to himself. The fact that he was eventually beaten down by the tyranny of the mob is inconsequential, for the moral victory was already won. It makes his defiance and steadfastness all the more admirable.