It would be helpful if you could let us know if the extension panel
appears on a Google Scholar profile page after you clear the browser
cache; restarting the browser or rebooting the machine will not clear
the browser cache. (If you know how to "force reload" a page or
disable the cache for a page, that would work as well.)
If clearing the cache doesn't work, then it would help us to know more
about your system: OS, browser version, whether you have other
extensions installed, and whether you are running in incognito mode.
Other extensions (eg, ad blockers) may interfere, so you could try
disabling them. The extensions is also not loaded in incognito mode.
It is difficult for us to help you without details.
-Scholarometer Team