Unhealthy blood flow in the saphenous vein will cause increase in pressure in the vein and inflammation in the tissue. The inflammation turns the tanning system on and causes areas of the lower leg to appear darker, or to have hyperpigmentation. Treating the venous disease will eliminate the pressure, turn the tanning system off and improve hyperpigmentation.
Carolina Vein Center's blog 
Comments on: "Skin changes from Varicose Vein" (1)
Skin changed but the spot on the effected area will be fine after this treatment, i think it is better to treat it.