Possible Clues:

• Nettle rash
• Itchy skin eruption also known as nettle rash
• Ben with a twitch losing his head over a song about nettle rash
• Rash result of grasping the nettle?
• Nettlerash
• Primitive nervous reaction over song causes minor eruption
• Before song you are, I see, holding tea for audience - that's rash
• Rash to show up giving support to king in ancient city
• Climbing fruit tree's endless song causes complaint
• Itchy red spots on the skin caused by allergic reaction