I've had two sessions of the sclerotherapy on a small area of my leg. After the first session the patch was reduced about 50 percent and after the second treatment is up to about 80 percent gone. Took a couple weeks after each procedure to see results, and the patch initially got darker before clearing up.
The treatment itself wasn't very painful, just some small needle pricks, and went quickly. You do have some red spots around the injection spots for a couple days after treatment, but those went away. I didn't wear any special hose after the procedure, but I didn't exercise for a few days afterwards. No other side effects - no discoloration, swelling, etc.