Morag, I think it's Natrum Muriaticum. I advise a single dose of 200c.

My analysis wasn't helped by all three of my repertories having a different set of remedies under the rubric fear of spiders.

Wait to see what others on the BB say, but if this were my patient, that would be the prescription.
Really it's as well that the Mag-p-aust didn't help, as your daughter needs constitutional treatment.