Hi,
I can't say for sure either what the bumps are. But my hunch is that since they developed to the size they are in just 3 or 4 days, and because there are several of them, it seems reasonable that they may be a reaction to some substance which she hasn't encountered before.
But as others have recommended, I would get her in to an avian vet very soon to have her properly assessed/tested. It might be that the lumps will peak in size and then begin to diminish. If so, their reduction in size may take considerably longer than it took them to grow. But, again, their rapid growth in conjunction with their multiplicity is what makes me think they could be a reaction rather than symptomatic of a disease.
Get her to a vet though! And please post back when you have some news.
Best of luck