Changing light cycle after flowering

I only have 2 plants approximately 8 weeks old. Poor lighting, and no fancy nutes... just window light. They're small but healthy. Due to my northern latitude solar cycle, both have flowered on their own at about 7" tall with one distinct bud at the top of the stem. I see no more pistils at any of the nodes... just the top. Nice and bushy tops but small. Should I have done something to make the plants branch so there are more buds, or am I going to have to settle with the single top bud? Should I shock them back into a different light cycle for further vegetative growth?

im assuming you can reveg it. throw it under some lights with a 18/6 light cycle.