What do yuo mean straight inside? How many watts is your hps? Is it hydro? As far as I know, I may not be 100% right(90%), but if the plant gets shocked during the flowering stage, then it can turn hermie, thats if its a girl. If its a male, kill it. You will know in 2-3 weeks normally what sex it is.
Now, you box contraption, can you tell if there is any, any light leaks? Are you giving it any nutrients? I would go and buy sum if I were you. Buy sum kind of bloom plus for tomatoes to help with the flowering stage.