If your Pro Retouch 2.0 actions suddenly stop working (i.e. you run the action, paint on the mask and see no effect), check your brush settings. First, make sure your Brush Mode is set to Normal and that you are using a white brush to paint on the layer mask. If that doesn't solve the issue, make sure your Brush Opacity is set to something that you can see (anything above 30% or so should be sufficient.)
Still having trouble? Reach out via our Support link. If you want even faster help with your issue, attach a short video of the problem and/or a screenshot of your entire Photoshop window and your brush settings.