When using the Customize button in the upper right area of the 'Appearance -> Skins' screen, the next screen will always display the default settings for the current skin. You can customize a skin setting on this page and then click the 'Save Skin Settings' button. If you navigate from this screen, but later want to revisit the changes you have made, you can click the 'Appearance -> Customize' menu option on the left and this will present the current changes made to the skin selected for this site.
This image shows the Pressero admin Customize button in the upper right and the site menu selection 'Appearance -> Customize' on the left side.
Note: when you click the Customize button in the upper right, the left side will navigate to the 'Appearance -> Customize' selection, but the default settings will be displayed. You have to actually select and click 'Appearance -> Customize' on the left side menu to see your customized settings.