I wouldn't up it quite yet, if you give them higher temperatures their metabolism increases - if he's already thin and not eating that could make him lose weight faster. Are they statted? And how are you measuring the temperatures (using a thermostat, dial or digital thermometer)?
The key thing at the moment is to leave him alone as much as you can to let him settle in.
Something I forgot to mention is the humidity. As well as a humid hide you can also give the tank a light spray (I spray the leaves mostly), however not all owners do this. It increases the humidity and helps to keep them hydrated without the stress of a bath, they also may lick the water off the decor. I've found that, if I don't spray mine for a few days, they quickly become dehydrated and lose their appetite.
It may also be worth getting some reptoboost or avipro and putting it in the drinking water. This should give him a boost and help to stimulate his appetite.