I Google'd "how to lower blood sugar" and got 39,200,000 hits [thirty nine million two hundred thousand]. There's quick ways, natural ways, immediate ways, with diet ways, with or without medicine ways, all kinds of ways. Start at the top.
You give SO LITTLE INFORMATION in your post it is very difficult to respond. I assume you have been diagnosed with diabetes. What were you told about how to manage that condition? Diet? Exercise? Oral medications? Do you follow this regime? Blood sugars from 180-456 on a regular basis put you in real danger of serious diabetic complications. I suggest you see a doctor/diabetic educator and learn how to manage your diabetes ASAP.