You can restore your droplet from a snapshot or from any backups that you have. The first option is more convenient as it will basically restore the droplet to its original state. Snapshots are on-demand disk images of DigitalOcean Droplets and volumes saved to your account. Use them to create new Droplets and volumes with the same contents.
You can check this tutorial for more information:
The other option is to restore the droplet using backups.
Backups are automatically-created disk images of Droplets. Enabling backups for Droplets enables system-level backups at weekly intervals, which provides a way to revert to an older state or create new Droplets.
You can check this tutorial on How to Create or Restore Droplets from Backups
If your droplet is still listed in your DigitalOcean account but can’t access it via ssh or the DigitalOcean command line, you can use DigitalOcean’s recovery ISO to regain access and perform recovery operations, like getting access to an interactive shell, running fsck, or chrooting into the system.
You can check this tutorial for more detailed instructions:
The last option will be to use local backups of the files and databases of your sites/applications. You’ll need to deploy a new droplet, configure everything (web server and install any additional software) and then upload the files via SFTP or ssh.
Hope that this helps!