Not eating may be due to many factors, not eating may cause a series of complications. If shes eating now thats very good. From my experience, id recoment checking up at diferent vets, a specialist in exotic small animals, rodents especialy. I went to 3 vets some multiple times and the first two said the chin was fine, blood was fine. First vet botched up her leg so she couldnt walk propertly for months and had severe leg problems because of a failed attempt to take blood sample. Second vet took a blood sample fine but couldnt read the results correctly. Third vet noticed the blood urea was 12 times out of norm instnatly, and there was a tooth spurr that was going into her cheek at the very back ( 1st vet examined her teeth twice and didnt see it, second ,once for about 15 minutes and didnt see it.
It most likely was a bad kidney, a managable state that with luck could left the animal alive and well if properly medicated (could but didnt, she was getting on the upp and upp and then she just died suddenly hence were not sure it was the tooth or the kidney), altho that kidney could have been a complication not the cause. The spurr may have caused kidney problems due to bad diet, the kidney may have caused the spurr due to not eating and grinding teeth as much as she should have. It may have been something else. Chins are so small and exotic its hard to diagnose them and hard to heal them and theres not many specialists experienced with them.