course navigation

Here's my scenario: on each screen of my course there is a Course Outline, showing all of the sections and pages of the course. As the user progresses through the course the Course Outline shows where he or she is and the previous sections all have hyperlinks built into the text so if the user wants to go back and review something it's possible. The user can NOT move ahead except by the Next button.

(The Course Outline is a text field and I have a new version on every page because it needs to constantly change to show where the user is.)

My dilema is probably obvious - a user decides to jump back a few pages to review something, but how does the user return to where he came from? Most pages have actions that need to be completed before moving forward and the user could go back multiple times (i.e., currently on page 10, the user uses the Course Outline to go back to page 6, then uses the Course Outline to go back to page 5, completes that page and moves forward with the Next button to page 6...then wants to return to page 10).

Any ideas?

Thanks,

Doug