My watch was lost for 5 months. Just found and started charging. I had deleted the watch from my phone but it says it is still paired. How long will it take to charge. I only see a black screen with white Apple logo

Greetings Ellahr2020!

From your post we see you are running into some trouble with your Apple Watch not powering back on fully and trying to restore a backup to it. We can certainly help! First try force restarting that device to see if you can get past the Apple Logo: How to restart your Apple Watch. After that you can restore a backup if available with these steps: Restore Apple Watch from a backup.

Have a great rest of your day!