There is an option to un-hide the whole thread, but I think it's a logged-in feature. If you have a Mastodon account, you can click on the "open in web" link (at the bottom of the toot, to the right on the line where the date is), which will open it in your Mastodon dashboard. Then, there's an eyeball toggle on the top right of the toot which will un-hide everything at once.