Yes, you can put it back on the 24/0 light cycle. I grow autos and come across some plants that tend to do that. It will not harm it or stress it. Do that 12/12 for at least three days and than back onto 24/0. Just to be sure. But 90% of the time it will continue to flower on its own after inducing it to flower.
Some autos grow bigger and take longer to start flowering, depends on strain and pheno. If it is an auto then moving it back to 24 hrs light shouldnt herm it, ruderalis is very resilient.