I want to share my terrible story.
While I was at the “Dashboard“, I went to “Settings” (located at the bottom, left side) and clicked on “General“.
Where it says “WordPress address (URL)” I mistakenly changed for something else and … boom!, I had the same problem described here. I just got a blank page with no chance to log in again.
Do not change this address if you don’t know what are you doing!!! (never again). I learned the hard way. I had to uninstall EVERYTHING and start from the beginning.
Fortunately for me I just had two posts, so it was easy to restore the information but once that you are back again in your blog, don’t forget to go under “Appearance” and click on “Widgets” to make sure that you are adding the “Meta” widget.
This will help you to log in from your Blog at anytime. Just write your Blog address (where your Blog is located in the Internet) and you will see the link for you to log in.