I had the VeinGogh procedure 3 weeks ago and these are the marks/scars left behind. It doesn't seem to be improving. (Photo)

Scabs and redness is not uncommon after VeinGogh treatment.  It can last up 6 weeks.  It is important not to rub or peel off the small scabs that appear after the treatment.  Give it time as you are in the middle of the healing process.  Moisturizer and healing agents will help with recovery and less chance of scarring. 

The Vein Gogh procedure causes tiny little scabs and inflammation post procedure. It can work well on tiny veins. We warn people that they may have rough minuscule scabs that may take four to six eeeks to go away. This is normal. Hope this helps 

Hyperpigmentation is likely after procedures to eliminate spider and reticular veins, i.e. laser or sclerotherapy. Topical creams should be used to reduce hyperpigmentation after laser vein ablation. I recommend a product called Scleroquin which can be applied twice daily. It can be purchased from the link below.As well, it is imperative to wear medical grade graduated compression stockings and to avoid sun exposure. Hratch L Karamanoukian MD FACSCertified Vein Specialist (ABVLM) 

Following VeinGogh treatment, it is not at all unusual to have some redness, or marks on the skin. They very often look like little scratches, which we refer to as the "Cat Scratch Effect". These will slowly go away over time, but not necessarily in just a couple of weeks. Understand that these areas are not scarred, just routine post-treatment inflammation. In our office, we have a topical cream, called Dermaka, which we give to all spider vein patients, that with daily use, helps any pigmentation or marks go away much faster. Also, it should have been made clear to you that a single treatment will not get rid of all your veins, and generally a series of treatments are needed.

So I'm not a huge fan of Veingogh but I would say that I recommend Arnica gel or cream to all my vein patients.  Its over the counter and homeopathic.  It helps with any pain and discoloration.  As far as lack of improvement sounds like you need to find a true vein specialist so that they can evaluate you for more significant or deeper reflux (venous insufficiency)