What Are The Uses And Side Effects Of Humalog Insulin?

My husband is a diabetic and has just been put on Humalog. He was called out of town and forgot his pen. He is attending a luncheon and has chosen a very low carb menu item. It is going to be over an hour after he eats before he is back to his office where he can inject the insulin. Is it okay to take the Humalog after he eats, with what kind of effect on his blood sugars?