At the end of Out Of Time, Barry has to run so fast that he accidentally jumps back in time by approximately one day, and becomes the doppelganger he had seen running alongside himself the day before... To Be Continued.
The next episode, Rogue Time, picks up right where Out Of Time left off, and Future!Barry starts living the previous day over. But since he hadn't jumped back in time yet, for the next day at least, Past!Barry should still be around, but he never shows up. As far as we can tell, except for those few seconds when the two versions of Barry saw each other running beside them, there was only ever one Barry Allen in Central City that day. (And, just to make things worse, because Future!Barry prevented the tsunami from happening, Past!Barry would never have ended up jumping back in time, so there should have been two of them indefinitely!)
So what happened to Past!Barry? It's never explained on the show, but has anyone involved with the show provided any insight into what happened?