Sorry to hear it.
I was in the midst of writing this response when you posted that you lost the bird.
She won't be well till the pests sucking the life out of her are gone.
If they are still visibly crawling on her, treat again.
The reason the vet suggested to re-treat in two weeks is to kill...
Don't beat yourself up. Nobody is perfect.
I never heard of Boom. What is the active ingredient/s in it?
Did the vet tell you how often and when to retreat?