If you notice that you've forgotten the injection immediately, you can take the normal dose right after the meal. Do not take the meal insulin dose for carbohydrates if more time has already passed since the meal.
If you didn't notice the missed injection, but you feel the rise in blood sugar after eating, check the sensor reading or measure your blood sugar. A forgotten dose can be deduced from the blood sugar result as well as from the trend arrow on the sensor.
If you are certain that you forgot the mealtime insulin injection, you can correct high blood sugar with a correction dose based on your insulin sensitivity. If blood sugar continues to rise, it is not recommend to take another correction dose within two hours to prevent an excessive overlapping effect of the insulins. You can take an additional correction dose if necessary at the next meal, along with the dose for carbohydrates.