Clicking on the "Back" button repeatedly may or may not get you beyond this roadblock, depending on your browser and what pages it has visited. Whatever you do, do not click on the "Reload" button.
If you want to move back to a page you viewed before logging in, a better solution is to use the tool provided in your browser for displaying a pop-up menu of pages you have visited. This can usually be done by clicking on the "Back" button and holding the mouse button down, or clicking on a small down-arrow or "Go" pulldown next to the "Back" button. The browser's "History" function may also be useful.