Laser Hair Removal burns- faded from dark to white- permanent?

In March 3, 2014 I was burnt during a treatment- full legs! I used a mixture of hydroquinone(7%) and retin A (0.05%) that was prescribed. I used it nightly and the dark marks faded. Once faded it turned white! My doctor said its hypo pigmentation -likely from laser. The adjuster for the clinic says its the mixture I used that caused the white marks! I've used this mixture go 20 years on my face! I always use a sunblock! Did the marks come from the burns or the cream?