I plugged my external hard drive into my computer after downloading all my games from PS4. Now the PS4 won't read it without formatting it. Help?

Finally got an external hard drive for more space. Plugged it in, formatted as extended storage, downloaded all my games to it for a few hours. All went well. Then I (apparently stupidly) thought that I could use the same hard drive for some pc files. Plugged it into my pc, it did not work at all (not recognized, not under devices, etc), and I removed it without making any changes.

Now the hard drive is back in the PS4, and the PS4 wants me to format it again. I imagine that will delete all my games. What can I do?