Hi thanks for writing to healthcaremagic. You are suffering from a condition known as erythyma nodosum.It is an inflammation of fat cells in body under skin In about 30-50% of cases, the cause of EN is unknown EN may be associated with a wide variety of diseases, including infections (e.g., hepatitis C, tuberculosis, streptococcal, Mycoplasma pneumoniae, Yersinia, and Epstein-Barr virus), autoimmune disorders (e.g., inflammatory bowel disease or Behçet s disease), pregnancy, medications (sulfonamides, oral contraceptives, bromides), vaccinations, and cancer. EN may also occur in lepromatous leprosy.So it is always important to rule out causes,and it will be better you consult a dermatologist and undergo various blood investigations and punch biopsy of lesion. For relief you can take nsaids like combiflam.Take bed rest,wet compression and leg elevation can also help you.You can use compreesive bandages.In most cases disease resolves within 3 to 6 weeks.