Welcome! You'll find PM a great help for your workflow.
After you have updated things in PM, just have Lightroom synchronise the folder (right click on the folder to get this option). I do this all the time and works great.
Note: make sure you have Lightroom write its metadata to the files/XMP sidecars, and not to its own database! Also make sure you have PM's IPTC preferences set up correctly for maximum compatibility with Adobe software.