I agree with the sprinkle suggestion. Also, your profile says you have two chins, maybe you can let him watch the other one bathe. Put them in the same area but separated from each other, maybe by a baby gate or something, and give them each a dust bath. That is how kits learn to bathe when they are young, by watching their mothers do it.
I don't think anyone on here would have a problem with you buying a loving a pet store chinnie. Just no one should breed those animals because you have no information on their background. But eroomlorac is right, even pet store chins need love!