Nd:YAG laser for skin treatment turned my hairs blonde, is this permanent?

This can be typical, but it isn't permanent. Keep in mind, it will take a series of treatments to get improvement with laser hair removal. See an expert. Best, Dr. Emer

Hello nousernameleft,
What you are seeing now is blonde hair that was there but can be seen that the dark hairs are gone.  Laser hair removal lasers will not change hair color, their job is to destroy the bulb of the hair down in the root.  This can only be achieved if the hair has pigment.  The lasers will not treat blonde, red or grey (non pigmented) hair.