User blog comment:PUNCHURPREGNANT/Gray and Silver Predictions/@comment-24291661-20140110084107/@comment-7418318-20140110160140

I guess it's possible that in his future all healing magic practitioners are dead and he took a seriously wounded Juvia back into a time where some were still alive so her life could be saved, but she died before he had the chance to get to them.

Not that I think this is particularly likely (or desirable), but it's not completely impossible either.