I agree, appears to be dry fowl pox. Which is a slow-spreading viral disease most often transmitted by mosquitoes. There is no cure for the disease, but it should resolve on its own in a few weeks. Little can be done as far as treatment, besides applying an antibacterial ointment to the lesions on the face., and ensuring the bird is eating and drinking adequately.
I recently have dealt with fowl pox
And I did seperate her and applied cold sore treatment on her a few times a day and scans came off in a week and a half. I used the real expensive one Abreva. Some say diluted iodine works also. It's good to keep seperated til all scans fall off as they are contagious. Also I gave thee black peppercorns a day for three days to prevent spread to her throat. It's just like when we get chicken pox, it goes away