I had sclerotherapy 5 weeks ago on my leg which caused indentation.

It is difficult to picture what exactly happened. Occasionally large superficial veins when they shrink after sclerotherapy can cause a form of indentation but I can't be sure without actually seen it. Perhaps you could send a picture and I can try to figure out the problem.

It is difficult to answer your question completely without a picture.   If you had spider veins injected then there should be no indentation. If you had larger veins injected then they may actually get hard and appear larger and the area next to them would appear indented.  I would follow up with your treating physician.