Next WIP

As I start the editing process for The Boy I Once Loved, I'm already planning my next book. I'm currently torn between two books. I was planning to write the third and final book in my Hexborn series but this has been my least successful book series to date so is it worth investing my time in right now? Part of me things I should shelve this book for now and write my new PNR/FR book, Shadow Kissed.
My mind is currently invested in Shadow Kissed but my head is telling me to finish the Hexborn series. Decisions, decisions.