It went around my daughter's school. My baby has very long, very wavy, very thick hair. We got rid of it for months on end, but there was one girl in her class whose mom refused to deal with the issue, so we got it again... then again before the school forced her to stay home until it was taken care of.
Anyway, the OTC pestacides did not work. We tried that once but I couldn't put the poison on her again. What DID work for everyone at our school was Lice MD. It is available at Walgreens, non-toxic, and it just plain worked. With that said, we still picked every single nit out of her hair and went on searching and searching for months on end until we were quite sure it was all gone.
All stuffed animals were vaccuumed, bedding was boiled. Freaking nightmare.
I sincerely hope you do not have to deal with this. I also hope that that irresponsible mother does not arrange any more playdates until she takes care of her problems.