Open Photoshop and navigate to the plugin under the "Filter" menu.
for high-end skin retouching that don't require a license key? Portraiture Plugin For Photoshop Cs3 - Google Groups
: If you already own a license for Portraiture 4, the update to version 4.5 is free of charge. Additionally, Portraiture 5 is currently a free upgrade for all existing Portraiture 4 license holders. Legitimate License Management License Recovery