Having the option to work on different layers in the skin creator would really add a lot to it. This would be really helpful in improving workflow. I hope you are able to add this!

Edit: I was thinking that the layers would function in a similar way to art programs like photoshop. Ideally you would also be able to toggle the layers on and off and lock them so you don't accidentally work on them. Websites like MinersNeedCool shoes also have this feature but they all have very harsh downsides.