Possible Clues:

• What a blow it causes one to make beer, by the sound of it
• Souvenir from a trip?
• Skin injury
• Makes beer, we're told, causing injury
• Mark overheard plots
• Sparring souvenir
• Mark puts the kettle on, we hear
• Blemish on skin develops, we hear
• Sign of injury
• Injure underlying soft tissue or bone