Should my Juvederm have been saved?

I have a large bump on my nose bridge and after seeing the before and after photos I decided to get it flattened by juviderm injections. I was charged $500 for the vial and was later informed that we only used about half. my nose looked flatter but the net day I realized that there was still a noticable bump. because the doctor said come back if i am no 100% happy i figured that they could inject a bit more. a few days later I went in again and just as the doctor was about to inject the juviderm she informed me it would be another $500. I was never told that the rest of my juviderm that I paid for was being thrown away and that I would have to pay for the entire vial when we only needed a tiny bit more. after arguing that I had no idea the doctor began to say that I should have known that... how am I suppose to know that!? I am 18 and this is my first time doing anything like this. and now I have had two $500 injections and am still not pleased with the result. shouldn't the doctor have told me about this? or can juviderm be saved??