At least 26 people were killed and 103 injured in the collapse in Lahore.
Identified only as Shahid, the teen was among the unspecified number of missing, government official Mohammad Usman said. He appeared to be in stable condition.
Rescuers were carefully removing debris in hopes of retrieving more survivors, Usman said.
The rescue came hours after authorities said hopes were starting to fade for finding more survivors. Jam Sajjad Hussain, a spokesman for the Punjab Emergency Service, said the 400 rescuers saved the lives of 103 workers since Wednesday, when the building suddenly caved in.