Having too much insulin in your body occurs when you are either hypoglycaemic [hypoglycemic] OR it's an indication that your body's cells are resistant to the effects of insulin. i.e. you are a type 2 diabetc.
Having a hypoglycaemic [hypoglycemic] event occurs because homeostasis, which is where things are 'kept in balance'.
When you take too much insulin, your blood sugar (glucose) level falls below a 'prescribed' range. This is what hypoglycaemia [hypoglycemia] is.
To counter this imbalance, the alpha cells of your pancreas produce a counter-regulatory hormone, called glucagon, which stimulates the liver to 'give up' some of its stores of glycogen, which can quite readily be broken down in to glucose, which is then pushed back into your bloodstream.
When glucagon is produced, it inhibits production of insulin. This results in the raising of your blood sugar (glucose) levels .... assuming, of course, that you haven't taken too much insulin to begin with. (This can be extremely dangerous. You could lose consciousness; lapse into a coma; or even die, dependent on how low, and how quickly, your blood sugar level falls.)
Once your blood sugar (glucose) levels return to a 'normal' range, production of glucagon ceases and insulin, which is produced by the beta cells (islets of Langerhans) starts to be produced again.