Hydroquinone before Spider Veins Laser Removal?

Hello, I have some thin spider veins on my lower legs and thighs and the doctor recommended the Nd:YAG laser. She did say however that I would need to use hydroquinone for two weeks before the first session. My question is, how do I apply it? Do I only apply to the areas with the spider veins? Or full legs? And how many times do I apply it per day? Also, what strength of hydroquinone should I get? Thanks :)