Mix the oatmeal and milk in a small bowl. Mix the dry ingredients in another bowl. Add melted butter and the beaten egg in the oatmeal and milk mixture. Mix well. Pour wet ingredients all at once with dry ingredients. Mix just enough to moisten the mixture. Carefully add blueberries. Fill a greased muffin tin with the mixture, filling each muffin cup ¾ of the way. Bake at 400F for 15 to 20 minutes.