That's quite a severe case of Fowl Pox.
Are there lesions/wet pox inside the beak to or is it all dry pox lesions on the outer skin?
IF just Dry Pox (meaning no lesions/wet pox inside the beak) then you can try tube feeding her for the duration and see how it goes. This may take weeks and you'll need to be committed to tubing her multiple times daily.
For Turkey, she really needs the higher protein Gamebird feed to sustain her, you can try blending it in a slurry to tube her. If not, then using Kaytee baby bird forumula would be best I think it's around 22% protein.
There's no quick fix even for Dry pox, it has to run its course. It's usually best not to disturb the scabs since it can cause it to spread, but this is so severe, you may want to paint Iodine on most of them to see if that will help dry them up. Use your judgement around the eyes.
If it's Wet Pox, that's another story. A lot of times birds will die due to exudes/lesions blocking the airways, the tongue, etc. Tubing feeding may help and an antibiotic may help with secondary infection, but not always.
If you feel she's suffering, in pain or deteriorating then putting her out of her misery is certainly something to consider.
How to tube
https://www.backyardchickens.com/articles/crop-feeding.75454/
BYC Member treatment Fowl Pox
https://www.backyardchickens.com/th...pox-graphic-pictures-of-pus-and-scabs.818895/
Fowl Pox treatment
https://the-chicken-chick.com/fowl-pox-prevention-treatmen/
