How long does it take for the vein to break down after sclerotherapy?

I suggest you speak to an expert in sclerotherapy and laser treatment of veins. I give veins 2 weeks after injection to know if the treatment is working.  Best, Dr. Emer.

It will take up to 2 months before you see full results. If necessary to treat again wait 2 months, no earlier. You should expect at least 50-75% improvement of overall appearance with each treatment. Most patients may need between 2 to 6 treatments. If there is no improvement, consider to be re-assessed for venous insufficiency including ultrasound of your legs by your board certified vein specialist. 
Best,