Panacur is sweet, tastes great. You should be able to just put the dose with her food. I core-out a piece of carrot, apple or banana, stick the meds, put the cored part back in and leave it for them (if they don't take it from my hand) and they gobble it up.
Ditto with the pro-biotic. Its usually a good tasting powder, just sprinkle it on some pellets or treats a couple hours after the antibiotic. I use acidophilus in that manner.
The antibiotics are very important. Pro-biotics are advised but not crucial unless she shows signs of upset.
And I repeat: Not a lot of antibiotics are good for head-area infections, there's a hard-to-cross blood-brain barrier, Baytril is losing its effectiveness regardless, go for Chlor Palm. If you do insist on Baytril and it makes no difference after a couple of days, switch.
Lethargy is only a symptom in a VERY sick rabbit.
The infection can be there and under control in a well-nourished, happy rabbit, but once other factors stress the system, that can change suddenly and dramatically. A lot of it is holistic/supportive care.
sas