<s>[INST] hi, i have a question regarding my dads lower leg, specifically his calve and foot . it has been a month or so now that he has been having severe pain in his leg and it is red and swollen. the swelling has now gone down into his foot...the skin is very red and hard. Do you know what the cause is and how it can be treated [/INST] Hi, It can be due to bacterial infection. Need to send a picture of the affected part to comment more on it. Is he diabetic?  In case of uncontrolled diabetics skin and soft tissue infections in leg is a common issue. Do blood routine investigation and sugar levels in blood to rule out infection. In case of infection antibiotic therapy will be required. Hope I have answered your query. Let me know if I can assist you further. Take care  </s>