When your neutrophils are high it usually means you have an infection.
Having high neutrophils in your blood is called neutrophilia.
If your neutrophils are high you're at risk of developing bacterial infections which can be a wide range of different infections since there is not just one infection that you get when neutrophils are high.
Sometimes having neutrophils that are high may be a sign of cancer or put you more at risk of developing cancer but thankfully that is rare.
Even just having a mouth ulcer can be one of the infections when your neutrophils are high.
So don't panic when you do have high neutrophils as sometimes it may not be anything serious but in other cases it may be.