ICU on curezone has a protocol of taking albendazole 400mg twice a day for fourteen days, then taking a break for a week to rest a liver and repeating the cycle again. Apparently it can take a few cycles to eradicate worms.
I haven't dealt with pinworms personally as far as I know but maybe that could help the problem for some. As it is I may start albendazole again depending on my stool test results.
Albendazole is a pretty broad spectrum parasite killer as well so maybe it could help if taken multiple days in a row, a week long break and repeating if symptoms start getting better.