My message icon accidently got hidden, and now I don't know how to bring it back to home screen.

Hi

When looking for the Messages app icon, keep in mind that you may have moved it to a different Home screen and/or moved it into a folder (which may itself contain multiple pages of apps):

To search for the app, when viewing the Home screen on your iPhone:

• Swipe down on the centre of the screen > in the Search box at the top of the screen, type "messages" > when the Messages app icon is shown, it will also show (to the right of the app icon) the name of any folder that it has been moved to.
• You can also tap on the icon from within the search results to open the app.

When you have located the icon, gently touch and hold your finger on the icon until all of the icons start to jiggle, drag it to your preferred location, then remove your finger to drop it in place. Press the Home button when done.

When moving the icon, options include:

• Dragging the app to the edge of the screen (left or right) to move it to a different Home screen.
• Dragging it into the Dock at the bottom of the screen (you may need to remove another app first, to make room for it).

Another option is to reset your app layout. However, note that this removes all folders, restores the original wallpaper and returns the Home screen and all apps to their original layout (third-party apps are listed after built-in apps):

Go to Settings > General > Reset, then tap Reset Home Screen Layout.

you can try

settings->general->reset->reset home screen layout