How are you serving the veggies? Cut up or more finely chopped?
It's not so odd that he's preferring worms after hibernation, it's a quick way for him to rebuild any weight he lost.
What I do with mine is serve the veggies finely chopped, on terra cotta dishes under a shady plant or in a hidden part of the pen. I've noticed that my ornates are more shy about eating in front of me or out in the open in their pens when eating veggies. Anything goes for insects... Keep offering the veggies earlier in the day, everyday if you have to, and try to arrange it on the dish so that you can tell if it's been disturbed or if any has been eaten - don't stay around to watch and don't offer the worms till later and skip some days - maybe he'll try the veggies and figure he might as well eat. lol Try chopped and mixed in red bell pepper, strawberries, cantaloupe (when it becomes available), various berries, and tomatoes for color and scent - just make sure your turtle can't pick them out too easily.