We have a situation here where we cannot induce vomiting in a Dragon like we can in a dog or cat. The worst part of the Sago palm is the seeds, although all parts are toxic. The problem is we do not know what type of reaction you may get with him ingesting even a few strands of the palm.
I would like to try and locate a Herp Vet in your area and have you see if they have someone to see him on an Emergency basis. They may want to do a charcoal lavage or treat accordingly. At home we cannot really do anything except wait. If you can supply a State I will give you some Herp Vets. joan
These are links for Northern and Southern CA
UC Davis has a clinic that is 24 hours and does treat reptiles, but not sure of proximity to where you live.