Easy. Just make the glowstick/flare an item that acts like a grenade. When the grenade is thrown it becomes a projectile, which can very easily have its own light. Just change it so that the lifetime before explosion is long, and that the explosion itself is, well, nonexplosive and harmless.
this could be made in a day, but i'll let colonial kliler do it since i guess he has that handheld light pack