It’s very easy and simple to correct existing keywords that are misspelled.
Right Click on the keyword in the keyword in the right panel → select
Edit Keyword Tag or
Rename and type in the new spelling. You are done!
What about all the existing photos? It’s already done. How?
None of the photos are actually associated with the keywords. Here’s the table that configures the keywords. Each photo is associated the various
id_global. The keyword itself is associated with the photo only at display and export time.
Screen Capture of the Lightroom Catalog/Database Keywords