When Do the Knots and Bumpiness Disappear from the Injection Area After Sclerotherapy?

The bumps after sclerotherapy are usually trapped blood between 2 areas closed off.  Your doc will just simply nick the bump and release the blood clot so the bumps go away quicker.

Sometimes, the lumps are from non-threatening clots that can be nicked and extracted. This, when done, can decrease the chance of long term discoloration from the red blood cells and their iron. The lumps in many patients self-resolve without any long term coloration but can take 8 to 16 weeks, sometimes more.

This depends on whether the knots are clots or scar tissue. In the former, they tend to soften after 7-10 days. Scar tissue may take a minimum of 3 months before significant softening ensues.

Following sclerotherapy, it is imperative to get good compression of the extremity to prevent trapping of blood in the sclerosed veins. If such blood is entrapped, it is called a coagulum and needs local treatment with heat, ibuprofen and something called a Phlebitis PAK (neutraceutical). Another cause of the bumps is the 'leakage' of blood during the sclerotherapy procedure.A tiny puncture wound with an 18 G needle can drain this coagulum and reduce the likelihood of hyperpigmentation. It will also accelerate the healing process. 

Following sclerotherapy it is not uncommon to develop lumps and bumps in the veins that have been treated. This is due to two reasons-clotting of the treated veins and leakage of blood around the treated veins. Topical heat to the areas and NSAIDS will help to resolve these but lancing the areas with a needle under local anesthesia is an immediate solution. If left alone they should resolve on their own but this could take months. If you are uncomfortable with the lumps then draining them would be the best option.