It depends on what type of vitamin injection, not all can be harmful. I do agree that there are better ways to get vitamins in your tortoise though.
As I stated before, you should have your tortoise set up where he can be warm around the clock. This is where an enclosed terrarium of sorts is useful. There are many good ideas shared on the forum, I'd recommend searching around for "Closed Chambers" to get some ideas. You will have a much easier time maintaining the heat and humidity in that sort of set up versus an open top sort of set up.
You can maintain the heat with a ceramic heat emitter connected to a thermostat. This is what I use: http://zoomed.com/db/products/EntryDetail.php?EntryID=260&DatabaseID=2&SearchID=5
What's nice about the above is that it also controls the humidity when connected to to a small humidifier.
You don't need to keep him at one single temperature, but I do recommend that you keep it as stable as possible so theoretically, you wouldn't have a cool end. When the tortoise is better you can set him up in a more normal enclosure.
As I stated before, you should have your tortoise set up where he can be warm around the clock. This is where an enclosed terrarium of sorts is useful. There are many good ideas shared on the forum, I'd recommend searching around for "Closed Chambers" to get some ideas. You will have a much easier time maintaining the heat and humidity in that sort of set up versus an open top sort of set up.
You can maintain the heat with a ceramic heat emitter connected to a thermostat. This is what I use: http://zoomed.com/db/products/EntryDetail.php?EntryID=260&DatabaseID=2&SearchID=5
What's nice about the above is that it also controls the humidity when connected to to a small humidifier.
You don't need to keep him at one single temperature, but I do recommend that you keep it as stable as possible so theoretically, you wouldn't have a cool end. When the tortoise is better you can set him up in a more normal enclosure.
. I tried to give him his shot yesterday but don't think I did it properly. I think I may have hurt his little leg. I called another vet but honestly can't afford a second opinion (though May have to get some help cause I'm not sure what else to do). Trying t new enclosure since yesterday, in a Rubbermaid tub with a more moist substrate. I don't know what to do to get him to eat, it's as if he's rejecting everything but lettuce. Tried grass, dandelion, kale, Timothy hay... He's rejecting everything. Do you know what kind of plants I can get him for his enclosure from the garden centre? Any other tips would be Great 
