Thor grins at his brother's insult in a way that was quite befitting an infant. Thor gazes down at his arm expectantly, waiting for it to mend.

He knows Loki can do it. All he needs is some encoura --

Then suddenly, Thor's injured arm launches itself towards his face; his fist hits the top of his forehead. Thor stumbles backwards and then falls onto his ass, temporarily stunned by the force of his own blow.

His arm is still bleeding. His head is still spinning.

Loki just needed some encouragement.