Open mouthed breathing is a sign of a lower respiritary infection. (Runny nose/ bubbles are an upper respiritary problem) & I think Fortnum is the antibiotic most suitable to treat it. (It needs to be stored in a freezer & injected every 72 hours)
(I do appreciate its hard to pinpoint which type it is with a baby) ��
Hopefully the baytrill will help & I would carry on & complete the full course. Are you keeping her warm 24/7? Keeping them warm boosts the immune system which obviously helps the AB's to work.
You need to keep the soaks up to combat the dehydrating affects of this heat. I recommended you get some Abidec (orange box) available in most chemists/ supermarkets. Add half an inch in the pippet provided to a warm shallow bath & topup the water to keep her warm & happy to sit in it for least 20 minutes. Then rinse her off. Add it to one bath daily.
I had a failure to thrive Hermanns hatchling. She wouldn't grow past 15 grams. She was 15 grams for 2 years! Only grew once I started to use this. Dan on here explained to me that once a torthas been dehydrated they really struggle to absorb vitamins. This is why they can eat normally but don't grow
you need to "over do" the vitamins, together them in!
(Mine has continued to grow & is now a healthy smaller adult, but doing well)
What about nebulizing? Adding some F10 can really help (as can steaming if you don't have aneb, just shout if you need help with how to do this)