Will my python ever recover?

[Bogertophis]

......I will start the probiotics tonight if I can. I never used this before, how much powder do I put in the rodents mouth? Is the dosage critical?

.......To be clear. I noticed a little bit of blood coming from her mouth 6 months ago. I was on top of it immediately and took her to the vet. My vet suspected early mouth rot but wasn't certain. She then was put on antibiotics that day for an entire month. I would take her to my vet every 3 days for an injection. So, it's been about 5 months since the antibiotics. Also, the picture I posted of her mouth open was from about 3 weeks ago. The other pictures are more recent.

I know she anit no spring chicken, but I also didn't think 11 was old for a python. So the antibiotics can cause weight loss? ...

Dosage of probiotic powder is NOT critical at all- personally, I'd fit as much as I could into the rodents mouth prior to feeding. (A tiny funnel -even if you make one out of paper- will come in handy.) Your snake is large anyway, plus she was on antibiotic injections for a month! -that's A LOT & it's hard on a snake's body. (Dusting powder ON a rodent is less effective, since most falls off, plus some snakes may detect a different odor & could refuse to eat, which would be very counter-productive.)

I wonder how often your vet sees & treats snakes? If I only "suspected" mouth rot, without seeing actual signs of it, I'd not want any snake of mine treated with antibiotics- not only because they kill off the snake's good bacteria, but because UNLESS some lab work is done to make SURE it's the right antibiotic to fight the snake's specific infection, it won't even help. Harm without helping is not a winner. And the thing is, a little blood in a snake's mouth could be from striking the glass or slipping & falling in their enclosure, from their own loose tooth jabbing into their mouth, etc.

Antibiotics do not directly cause weight loss- but they screw up a snake's ability to digest food as well as they normally do, resulting in needed nutrition being excreted in stool rather than used by the snake's body. See? THAT is what causes a loss of muscle tone & weight. Antibiotics can also negatively impact a snakes other organs- notably the liver & kidneys (even in humans). Just like humans, snakes need those organs to function & be healthy. Keep in mind that while some drugs are empirically established to be safe for use in snakes, there aren't the extensive safety tests done for medications given to snakes as there are for humans. Also, in humans or any animals, some individuals tolerate medications much better than others.

That you saw this change in your snake only AFTER she was treated with antibiotics for a month pretty much draws a straight line (of blame) to the injections she received.