Help! I’m locked out of editing my settings

Can someone please help me? I made the mistake of changing my blog address to a domain name of mine — When I clicked on mydomain/blog1 I used to go to my dashboard. Now I go to my domain — I can find no way to get back to the dashboard now to change the blog address.

Again, the address mydomain/blog1 used to take me to the dashboard — now it doesn’t and I don’t know how to get back to the dashboard to make changes.