If the internal storage is damaged there are only two options. One get it replaced. This would require contacting the manufacturer if it is under warranty, or trying a local tech if not under warranty. Or two, get a new device.
Now, since it is possible it isn't damaged, especially if you are just getting a message when you get into the phone saying it is, I would try starting up the device in "Safe Mode" and see if it will load. If it does, then you probably have a bad app, virus, malware, etc that needs removing. If it still won't work correctly and gives that message, then the two options above are what you need to do.
To get into "Safe Mode" please do the following.
1. First turn off the phone.
2. Next press and hold "Power" until you see the manufacturers logo on the screen, then release the power button.
3. "Quickly" press "Volume Down" and hold it for few seconds until you see the message "Safe mode: ON" or something similar.
4. If you wanted disable it, simply repeat the steps above, and you should see "Safe Mode: OFF" rather than on.