The Voyage of the Dawn Treader
How we cite our quotes:
"So I started scratching myself and my scales began coming off all over the place. And then I scratched a little deeper and, instead of just scales coming off here and there, my whole skin started peeling off beautifully, like it does after an illness, or as if I was a banana. In a minute or two I just stepped out of it. I could see it lying there beside me, looking rather nasty. It was a most lovely feeling." (7.38)
Eustace's transformation into a dragon is instantaneous (we assume) and occurs almost painlessly while he sleeps. The only pain is caused by the bracelet stuck on his arm when it turns into a thick dragon foreleg. But his transformation from a dragon back into a boy is a much more difficult, painful, and messy process.
"Then the lion said – but I don't know if it spoke – You will have to let me undress you. I was afraid of his claws, I can tell you, but I was pretty nearly desperate now. So I just lay flat down on my back to let him do it.
"The very first tear he made was so deep and I thought it had gone right into my heart. And when he began pulling the skin off, it hurt worse than anything I've ever felt. The only thing that made me able to bear it was just the pleasure of feeling the stuff peel off. You know – if you've ever picked the scab of a sore place. It hurts like billy-oh but it is such fun to see it coming away." (7.41-42)
Eustace was able to make himself hard-hearted and selfish, but he's not able to strip away his outer "shell" and get back to his true nature on his own. For that he needs Aslan's help.
"And there was I as smooth and soft as a peeled switch and smaller than I had been. Then he caught hold of me – I didn't like that much for I was very tender underneath now that I'd no skin on – and threw me into the water. It smarted like anything but only for a moment. After that it became perfectly delicious and as soon as I started swimming and splashing I found that all the pain had gone from my arm. And then I saw why. I'd turned into a boy again." (7.44)
Aslan seals Eustace's transformation from a dragon back into a boy with a baptism-like dunking in a miraculous pool.