The Facebook widget does allow you to change the width in the widget settings, but there is not a setting to change the height. If you need to change the height, follow the steps below. This information below was submitted by user lluisarbos
1. Go to editor
2. Find facebook-like-widget.php
3. Change “height” value as you want:
Please note this is a customization that is outside of what we can provide for theme support. If you perform the customization, you will need to maintain the changes for future updates and also be able to troubleshoot any issues that arise. Thank you.