I Am Concerned About My Grandchildren Every Time I Turn

I am concerned about my grandchildren every time I turn around they have lice and we do treatments and it gets better for a week or two then here we go again I became morn concern when I treated my granddaughter last night and they were tree scabs on her head also. is it possible it could be body lice and we treating for head lice I have no money for payment ofmany kind