The Nd:Yag (1064nm) wavelength is best for hair removal for darker skin. It is actually safe to use on all skin tones, but it is the best one that should be used for darker skin tones due to risk of burning the skin and actual results. The hair follicle underneath the skin is the target for the laser, therefore, this laser is best able to differentiate the color of the hair follicle vs the pigment of the skin in darker skin tones. If you are tan, I would wait at least 4-6 weeks for your treatment. During your treatment, wear sunscreen or cover the areas you are getting treated to avoid burns. The number of treatments usually depends on the coarseness and density of hair. The more coarse and dense, the more number of treatments. Typically however, the average (again depending on many factors) for darker hair on darker skin types is 6-10 treatments. As for now, wear sunscreen and try to keep the area covered for your treatment.