Possible Clues:

• Sore swelling caused by poor Bill being shackled?
• Swelling on a hand or foot, caused by exposure to cold and humidity
• Forged bill in M&S or Aldi, say, a source of irritation
• Painful swelling brought on by cold
• Bill upset in necklace perhaps causing inflammation
• Inflammation from exposure to cold and moisture
• Painful swelling on the skin brought on by cold
• Painful swelling on hand or foot caused by cold
• Painful swelling in winter
• A chap on foot?