In cases where people have crusted scabies it is likely traditional scabies creams are not penetrating the skin as they are made for people who are diagnosed and treated immediately. Also having a child you can not use permethrin based treatments as they can be dangerous. I would suggest you try using different scabies treatments such as
Naturasil scabies creams here. They even have sulfur soaps which have exfoliants and will help at bringing your skin down to its initial layer. Scabies burrows and tunnels and the longer you have them the harder they are to get rid of because it creates some kind of protective layer which protects them and thier eggs. Likely your skin is scarely in areas and feels thicker than normal. I highly suggest you try out the creams and soaps. Here is the website below;
Scabies creams and sulfur soapsIf this does not work which I am sure it will the only thing left would be to visit a doctor and ask for invermectin which is an oral medication for advanced scabies outbreaks in which you can use with the creams and soaps.
This should help!