Hello,
What meds is he on currently? You could try to get some acidophiliz which helps with restoring their gut flora & balances out their appetite more. You can get that from
www.reptilesupply.com
Those lights do cause alot of problems, & the reason that he had parasites was most likely due to the increased stress of the lighting, unfortunately. It isn't your fault, & you caught the problem. It will just take him some time to get back to normal.
You could try to get some bee pollen, royal jelly & brewer's yeast & mix that up with some water to help stimulate his appetite as well. It works pretty well. You can find those ingredients at most health food stores like GNC.
Tracie