HI,Dear,Welcome with your query to HCM.
Based on the facts of your query,You seem to had itchy area on inner calf,which turned into hard knot,which got bigger manyfolds in a day.This lump starting with itch,seems mostly from a clotdeveloped due to Idiopathic Thrombocytic 
Purpura.This has molstly occurred from stressed short saphenous  Venous system,cauising sucutaneous hemorrhage and which developed in to painful knot.
Aim of Treatacment-
As ITP is auto-immune treatment,
Prednisone is main treatment.
Overlap of 
Varicose veins needs to be investigated and treated along with 
Platelet transfusion.
Treatment would be-
Rest 
Elevation
Platelet transfusion by Plasma Infusion.
Steroids /
Prednisolone under cover of Physician
Compression /Cold Compresses.
Hope this reply would help you.
Welcome for any further query in this regard.
Will appreciate writing your feedback review comments,to help the needy patients like you at HCM.
Good Day!! 
Dr.Savaskar,
Senior Surgical Specialist
M.S.Genl-CVTS