His beak might be a bit deformed, but it will be fine. Then an even greater thing happened. After the vet had trimmed his beak and I got him home, gave him some food, Pesto went to sleep GRINDING his beak! I just about jumped and shouted for joy. But I kept it in, not wanting to wake him up. It is the sweetest sound ever! And my boy is now back to 98% of his old self. I don't know what the vet said to him while he was under, but since Saturday, Pesto has talked and kissed and wistled and just been amazing. Yesterday, I fell asleep on the couch. Woke up when he flew onto my shoulder. We slept like that for 3 hours. I am very happy. It has taken a month and a half, but he is just about his old spritely self! 
Also - in general for all of you who are worried about your bird's weight. I asked the vet to weigh Pesto on Saturday. He asked me why and I said I just want to keep an eye on what is happening with his weight. The vet then said that the only time he really pays attention to weight is when he has to administer very precise medication. All other times he uses the breast bone(I think the technical term is keel bone, or something like that). If it is rounded and smooth, then the bird has good body and muscle mass. If it is pointy and sticking out, then you have a problem. It's like in humans. we all are human, but we are all different heights and weights.
I have to go now. Have about 100 emails to send to people wanting to know how Pesto is doing! Thank you all for the support and the amazing advice you all gave me. I wish I could share my vet with you all. He really is amazing and I think every bird owner on this planet needs one of him!
