I don't know why they gave your chameleon an A/D vitamin shot....but as you know...what has to be done is to get the balance of nutrients back first and then go on a maintenance supplement schedule.
Here's some information I hope will help once its back in balance...
The calcium, phos., D3 and vitamin A are important players in bone health and they need to be in balance. You need to look at the supplements, the food you feed the chameleon and the food that you feed to the insects when trying to balance them.
Appropriate temperatures also play a part because that aids in digestion and thus indirectly in nutrient absorption.
UVB also plays a part because exposure to UVB allows the chameleon to produce D3 which allows it to use the calcium in its diet.
Gutloading/feeding the insects a good diet is important too. You can feed crickets, roaches, superworms, locusts, etc. a wide variety of greens (dandelions, kale, collards, endive, escarole, mustard greens, etc.) and veggies (carrots, squash, sweet red peppers, sweet potato, zucchini, etc.)
Since many of the feeder insects have a poor ratio of calcium to phos., its important to dust them at most feedings with a phos.-free calcium powder just before feeding them to the chameleon. By most I mean all the feedings but the ones that you use the D3 and vitamin powder at.
I dust twice a month with a phos.-free calcium/D3 powder to ensure that they get some D3 without overdoing it and I leave them to produce the rest of the D3 from their exposure to the UVB. D3 from supplements can build up in the system and cause health issues. D3 produced from exposure to the UVB shouldn't as long as the chameleon can move in and out of it.
I dust twice a month with a vitamin powder that contains a beta carotene source of vitamin A. Beta carotene (prOformed) vitamin A will not build up in the system like prEformed vitamin A will. Excess prEformed (acetate, retinol, retinyl) may prevent the D3 from doing its job and push the chameleon towards MBD. This way, if your chameleon does need prEformed vitamin A the amount given can be controlled by you.
I hope this explains it.
Here are some sites that might help too...
http://web.archive.org/web/20060502...rnals.com/vet/index.php?show=5.Vitamin.A.html
http://web.archive.org/web/20060421.../index.php?show=6.Vitamin.D3.and.Calcium.html
http://chameleonnews.com/07FebWheelock.html