No, whichever path you've chosen you left Floatsom with pretty good reasons not to go back, never mention the fact that Act II takes place really far away from that hellhole. So no turning back.
However don't worry - you didn't miss much, just some loot if I remmber correctly. You'll pick it up on another playthrough, or if you are really curious, reload a save from Act I, before starting the last mission.
Thanks :) yeah I made sure to do all the quests before progressing. I figured I hadn't missed much just some loot