How do I fix my address for my blog when I accidentally changed it to an html?

Changed address to my blog, now it is in html. I accidentally copied and pasted a google address in the line for my address for my blog.
I can’t get back to my dashboard page where I can make my changes. When I go to find it, I am taken to my front page of my blog and it looks horrible. As you can see I am new to this. Please help!! I need instructions in lamens terms if possible.