He attempted to use the pen in his car and the battery exploded, melting plastic in the vehicle.
The shop owners called an ambulance.
"When they x-rayed him, they found the stem, the metal embedded to where the blood flows up to the brain," Brown's grandmother, Alice Brown, told WFAA News.
Doctors were unable to remove the metal. Brown was placed in an induced coma, but died.
A similar incident also killed a Florida man last May.
Officials said 38-year-old Tallmadge D'Elia of St Petersburg died when his exploding vape pen sent two fragments into his skull. He also suffered burns on about 80 per cent of his body. The death was ruled an accident.
Malfunctioning e-cigarette batteries have caused hundreds to thousands of injuries, the BBC reports.
- AP