Are There Comment Text Revisions
Do comments have revisions like posts and pages? If so, how would you access those revisions?
No, WordPress only provides revisions for posts.
The “History” link on the admin/comments page does not show any editing/changing/updating of the comment, whether done by the admin or the original commenter.
This is actually added by Akismet and not something WordPress itself provides. It acts as a moderation history of sorts, but only Akismet related actions e.g.
Note that I’d edited the comment pictured, yet that edit was not recorded.