Not Enough Botox?

I had Botox injections for the 11's between my eyes. I thought I was looking angry even when I was happy.

I was very pleased with the results. Hardly any pain, just a little redness and a bit of swelling that was gone in a couple of hours. Very satisfied and will have procedure again.

I noticed that when I tried to raise my eyebrows only the outer part raised up. Looked like Mr. Spock or Jack Nicholson! How much Botox should be used and where should it be placed to prevent this?