In my experience vitamin “A” injections are most often fatal. I have seen tortoises a few days after an injection and their skin just sloughs off. I sell lots of my captive hatched tortoises, which are completely healthy and too many well-meaning buyers immediately take their tortoise to their local vet for a “Vet Check”. The vet says the tortoise is fine but gives a vitamin “A” injection for good measure and a few days later the tortoise is dead. If you are going to give a vitamin “A” injection you need to have a very qualified tortoise veterinarian do it as the slightest overdose will probably kill your tortoise.