@Kake Pick up your kitchen knife. The grip is just an extension of the blade with pads crewed to the sides of the base. The metal of the grip is still exposed directly. This, BTW, is why one of the more common cases of electrocution in the world is someone poking the wall plug with a kitchen knife.
I think the worms work like insulated batteries. She cut through the skin, that's why she was electrocuted. The charge was sufficient to jump to her hand but not past that.