I'm familiar with kinks in the spines of you corns. In them it can be caused by too much line breeding or spikes in the last week of incubation temps. In a year old rough green snake it is probably a broken spine. You could take it to a good vet to find out for sure. In the mean time I would leave it alone in its cage undisturbed for at least 5 days for rest and recouperation. Then try to feed it. If you do have to put it down the freezer works well.