Delayed Hypopigmentation After Laser Hair Removal

The 1064nm. laser is the least apt to cause hypopigmentation but no treatment is immune from risk.  You may have normalization occur spontaneously but it may take a long time. Some patients may try to intentionally tan their legs but it may accentuate the difference between the darker tanned color and the white spots. More importantly, you should not purposely expose your legs to the sun as the hypopigmented spots may be severely damaged by the ultraviolet rays and you don't want to increase your risk in your later years of developing skin cancer.

From your picture it does look like it may be hypopigmentation secondary to the laser treatment. This is a rare complication but does occur.  In almost all cases, it will resolve over time (several months).  Sun exposure may help but may not be advised as hypopigmented skin is more susceptible to burns.  I have seen patients treated elsewhere who come in with this complication and to date none have remained permanently hypopigmented. The fact that you had no blister or scabbing makes it even less likely to be permanent.  Remember the laser is looking for pigment in the hair follicle and if your skin was tan it may treat the skin pigmnent first.  Lastly, some lasers use a cold spray every time they fire which yours may have done (a spray sound and burst of cold each pulse) .  If so,  your pigment loss may be a result of the cold spray and not the laser beam and in this case it is unclear if it will be permanent.

Hypopigmentation after laser hair removal is seen very rarely in fair skinned individuals, the darker the skin the higher the risk of permanent hyopigmentation. I am not aware of any good treatments for this proplem. Tanning will probably just make it more obvious.