Yikes, that is so tiny. I would hold treating him with Revolution till he has stabilized (pooping/peeing regularly, starts putting on some weight). ...
Two of my babies are 48g and one is 51g , I've had them for a week and a half and all 3 of them have steadily gained weight and appearance wise look...
Weigh her? She lets you hold her?
There are meds used for balance issues, I'm not positive what they are but others here can help if that in fact is...
Make sure it does not smell rancid... we're not sure if it's that some folks' room temp to very warm, humidity or some other factor but it does often...