How does the inside of the beak look?
Is she on a seed or pellet diet? How does it feel?
I do not have first-hand experience with Psittacines but it appears to be some sort of inflammatory proliferation in the cells due to injury, but a virus, such as avian pox might be possible. If you have a vet familiar with birds it may be best to take her, otherwise, maybe apply iodine, or an antibacterial to the lesions a few times a day and see how she does.