The picture you provide is not telangiectatic matting (which occurs late) but rather typical changes following sclerotherapy. It will look worse before it gets better cosmetically. It is very very important to wear compression stockings in the injected areas to help prevent pooling of blood which is responsible for the discolored (thrombosed veins). The idea for compression after sclerotherapy is to prevent blood from coming back into the injected veins and prevent stagnant blood which clots and causes a inflammatory reaction where the endothelial lining of the vein leaks the red blood cells which release hemoglobin ( the molecule that carries oxygen) which deposits under the skin. The hemoglobin molecule contains iron which oxidizes and gives this rusty appearance (hyperpigmentation). Early on in the process, inadequate compression gives this brown green discoloration.
So, make sure you wear stockings and use topical products like VenoQuin and VenoLucent that reduce this hyperpigmentation and helps cosmetically improve the appearance of sclerosed veins.