First of all you need to figure out why there is pee soaking her bottom fur. The two most common reasons are a dirty cage or illness. My guess based on your other post would be dirty cage, since you don't have anything to absorb the pee. As I said before one piece of fleece isn't going to be enough to soak up pee for a week, even multiple layers often need to be changed a few times a week. Have you started washing the fleece daily now? If not basically she is just sitting in her own pee.
If that continues it will cause her to get a urinary tract infection and urine burns, and require vet care to treat and round the clock care (as in meds and possible hand feeding every few hours for days or weeks). Since chins are exotics, vet treatment can often quickly run into the hundreds to thousands of dollars, so obviously it's better for your chin and wallet to not get to that point.
Once you get that sorted you can add about a tablespoon of corn starch to the dust bath, over time the pee staining will go away (gets a bit lighter with each bath). Unless you live in a very dry place you can probably do a couple baths a week. You can also use organic unscented baby wipes to try to clean some of the pee off, and then give her a dust bath.
