about a year ago, i went to the past for the first time, looked around for a bit.. didnt really know what to do. i got a party invite, so as a blm i warped out of instinct... now i cant get back to the past?
Try going through the Maw in Batilla Downs, you should be able to get back in. You can't go through other maws in the present unless you go through them from the past, that's how you activate them. Once you get through the maw make your way to whatever city you want to be in for the war, that should allow you to Retrace there.
I know your hesitant in saying this...so i'll say it with you...Red Mage Rox your Sox!