I hope that you can get the hair to dissolve. The depilatory cream seems very harsh on skin, but hopefully it will work. There could be some scar tissue forming that acts like a tourniquet, so I would keep the skin cleaned daily with betadine and put a dot of neosporin on it.
How is the foot looking today? It is always hard to inflict more pain with getting an embedded hair or leg band off, but the outcome will be loss of the limb, so it would be worth the pain. This is very common with small chicks.
This happens frequently with strings accidentally dropped from...
If you have a seam ripper or a very small pair of scissors, I would try to slip them under whatever it is, because it can cut off circulation and the foot will die. Could there have been a leg band on that got too small. A string or a hair is the usual culprit in thes situations.