updates usually take up to 2 weeks to fully roll out during which time some sites that have been wrongly affected could recover.
I'd do nothing for 2-3 weeks. If your site doesn't recover after 3 weeks check what the update broke and fix it. This month's update is content oriented AFAIK, so you probably need to improve or update the content of the pages that lost rankings.
It could also be an internal linking problem (sometimes, pages without internal links pointing to them lose rankings), so you should point a few internal links to the affected pages, from pages that are in good standing and which are relevant to the content of the affected pages