Earlier this week, Damon, 36, pinched a nerve in his neck while feeding and holding his daughter as she slept.
“My 14-month old daughter Isabella did me in — something no killer can,” he joked to the German newspaper Bild.
Damon soldiered on through the Berlin premiere of The Bourne Ultimatum on Tuesday night, signing numerous autographs for fans who had waited to see him, and posing for many who wanted to take photographs of themselves with their hero.
But he was a no-show at the party afterwards, citing pain from his pinched nerve for his absence.
HE was sporting at least four tiny gold needles in his ear where an acupuncturist had tried to reduce his pain.
The acupuncture got Damon through the premiere, but he left the afterparty hosting duties to co-stars Edgar Ramirez and Julia Stiles.
When Damon left Berlin on Wednesday afternoon, he was reportedly a wearing neck brace.