A data storage device is disclosed comprising a first head actuated over a first disk surface, wherein the first head comprises a laser configured to heat the first disk surface while writing data to the first disk surface. A write power is applied to the laser and a first write operation is executed to write first data to the first disk surface during a first revolution of the first disk surface. A first transient decrease in an output power of the laser is detected during the first write operation, and when the first transient decrease in the output power of the laser is detected during the first write operation, a write-verify of the first data is executed during a second revolution of the first disk surface.