It sounds unlikely to that it's related to the cut if it was that minor and is now healed. It's possible he strained or fractured something in his SI/ pelvis etc. if he was caught in wire. Is he older? Does he move around much on his own? I would probably back off and re-start him much more lightly, with a couple of weeks of mostly just walking in increasing amounts (especially hills) and build up to asking for trot/ canter. If he still feels off at that point, get a vet to evaluate.