How long does it take for overall redness on cheeks to fade post accutane?

Generally, I would say the redness will last a total of 6-12 months.  You can definitely speed the process along with using pulse dye laser.  Generally, some doctors won't use laser until about a year after finishing Accutane.  However, in practice, many of us will use this type of (nonablative) laser sooner without any issues.  Pulse dye laser can greatly expedite the process.  And finally, sometimes there is still residual redness that lasts after the one year mark.  That is when laser comes in very handy.