Hello, Your friend had been taking Cephalexin, side effects of cephalexin are commonly diarrhea, itching / rash, joint or muscle pain, blistering, peeling, or loosening of the skin, chills, cough, leg pain, tightness in chest, etc. The side effects need immediate medical aid and management. Since the wound is still open and infected you are suggested to visit ER, get it cleaned and get antiseptic dressing done. He may need injections (antibiotics) for better and faster recovery. You can switch to taking a course of antibiotics orally after the infection is under control. He can take Combiflam or Naproxen, one stat when needed to get relief from pain and to reduce inflammation around the wound. Get dressing (cleaning and antiseptic dressing) done in ER every alternate day. Give rest to the foot affected. Your friend has a history of severe breathing problems due to work related chemical exposure, he also has respiratory infection and sinus problem. Your friend is suggested to get clinically examined by a GP, get X0ray PNS to detect nasal septum deviation, X-ray chest AP and Lat view), sputum and swab tests done to detect COPD or any pathology in the lungs so that treatment can be started at the earliest. To get relief from cough he can gargle his throat with warm salt water three times a day and to prevent allergic cough he can take non sedating antihistamine, one SOS when required. Help him stay away from addictions if any. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician