So I did some deflickering saved my lightroom catalog and all of the metadata...and want to go reexport a sequence from lrtimelapse. How do I get my previous project to open, or do I have to reimport it from lightroom and do it all over again from scratch?

If you didn't check the box "delete intermediary/temporary files after export" in the exporter, the intermediary files (LRT_* folder) should still be there and you can render again.
Just go to File/Render, choose the intermediary sequence, set your settings, and render.