Apple Cider Vinegar does lower blood pressure but it doesn't usually lower blood pressure immediately.
When I take Apple Cider Vinegar to lower my blood pressure my blood pressure takes an hour to lower from being high.
So within an hour or two hours your blood pressure should be lowered after taking the Apple Cider Vinegar.
You can also take Apple Cider Vinegar before bed which will also help you fall asleep as well as lowering your blood pressure.