Just to add some info here.
Baytril is extremely basic. Injecting it under the skin can be painful and cause pain to the chin and damage to the tissues - because it is so basic it reacts with the fat under the skin and burn. Burns caused by basic substances can be very severe and painful.
It should be given into a muscle, I prefer the large muscle in a back leg. However, you need to know where and how to give this injection to prevent causing any injury to the chinchilla.
Giving the chin the medication orally may not be the best option for appetite and the digestive system, but it is much easier for a vet to instruct a chin owner to give it this way. It will work just as well as injecting it. A healthy chin that has just has a wound but is still eating should be able to withstand one course of treatment with Baytril as a preventative to keep the wound from becoming infected. There may be some impact on appetite, but that usually resolves itself soon enough. Chin owners need to watch the appetite and energy level of any chinchilla on any medication.
In the future it may be better to request a different antibiotic like Chlorpalm. It is very effective with wounds and abscesses and has a little less of the digestive upset. Most of the more broad spectrum antibiotics can have side effects.
I'm glad that Molly is still eating. I hope that she heals up really soon. You can get unsweetened canned pumpkin at most any grocery. But, if she's still eating on her own, let her eat and just give her some probiotic on her food or in a syringe with Critical Care to help counteract the baytril a bit.