Accidentally selected delete

If you have deleted messages from your iPad, you may be able to recover them from a backup:

Recovery from a backup is only available if you had not previously enabled Messages in iCloud.

Settings > [Your Name / AppleID] > iCloud > Messages

These support pages outline restoring your iPad from a backup:

Restore your iPhone, iPad or iPod touch from a backup – Apple Support

Restore all content to iPad from a backup - Apple Support

You’ll need access to either a Windows PC (with iTunes for Windows installed) or a Mac (with iTunes or Finder - as appropriate for the installed version of MacOS).

Download and use iTunes for Windows – Apple Support

Update to the latest version of iTunes – Apple Support

Use of a PC or Mac computer is unavoidable. If you don’t have access to a suitable computer of your own, that of a helpful friend or family member will suffice. Alternatively, the technicians at the Genius Bar of your local Apple Store or Apple Authorised Service Provider (AASP) will be delighted to assist.

Genius Bar Reservation and Apple Support Options - Apple

No, what you need is a backup - you can recover them from there.