I just did this with a plant. After being born in 12/12 and staying there for a month it showed its sex. I wanted a mother so I put it under 24/0. It really slowed growth a lot and each new node had like two little hairs. Some of the slowed growth could be attributed to it being topped, and the two new tops being held down with fishing weights (stress).
I was going to leave it 24/0 all year but I ordered some Wonder Woman seeds yesterday. Since the plant is bag seed I decided to finish it out in 12/12 and use a WoWo for a mother instead.
I've heard putting them back into flower can cause them to hermy down the road, but that would still be further down the road, if it happens. I've never had a hermy and I open the tent whenever I feel like snipping a branch to smoke, regardless of the light. I even flip the light on so I can see. And you don't have to dry it out if you don't feel like waiting. Put some in a bowl and smoke it. You'll wish you hadn't later though, when you realize it would have tripled in size and potency. I do it anyway, I'm a feign.
Personally I wouldn't put it back into veg. I bet within another 3 weeks you'll see its sex. I'd plant another one and leave it in veg in the meantime. You guys are going to smoke this thing up so fast anyway, you'll want more plants ready asap.