Another Chinchilla Question?

So, in my last question, I was talking about how my chinchilla picked off the fur on his right front leg. I was just wondering if I should still give him a dust bath if he has no fur on that leg? I mean, there is skin and no open wound, but I don't want to dry out his skin with the dust. Also, he is kind of a big boy, and the new ceramic dust bath I bought him doesn't let him roll around like he loves to, so any suggestions on what dust bath I should buy him? I can't spend a whole bunch of money on it, $30 is probably my limit. Thanks!!