I found the solution, but here is the answer in the event others need it. Add the following in your module class. Keep in mind I would use the setting.js with the help of FLBuilder.registerModuleHelper() and its functions before using this method when possible. settings.js is good for smaller validations and snippets. The below method is good for third party scripts or css files.
function enqueue_scripts(){
if(class_exists('FLBuilderModel') && FLBuilderModel::is_builder_active()){
//jquery expose for highlighting section of the widgets to edit
$this->add_js('custom_js', $this->url . 'js/custom.js', array(), '',
$this->add_css('custom_css', $this->url . 'css/custom.css', array(), '', true);
}
}