If you’re asking how to go back to the main story from some exposition, my answer is cut out the exposition and stick to the story. Whilst I can’t speak for all readers, if there’s one thing I find very frustrating are filler paragraphs that contains meaningless, directionless drivel of a place, character’s inner thoughts or whatever that doesn’t contribute to the story. Chances are also it’s not going to be interesting to read anyway.
it sounds like you’ve got into the trap of writing filler paragraphs and are lost in how to get back to the main story.
when it comes to editing your work, always get rid of what you don’t need; what’s not driving the story forward?