Think for a minute about the little bumps on your tongue. You probably saw a diagram of those taste bud arrangements once in a biology textbook — sweet sensors at the tip, salty on either side ...

The arterial blood supply to the submandibular nodes arises from multiple parts of the facial and lingual arteries. Venous blood drains into the deep lingual vein.

Amy Revell, 17, from Stirling, developed the lump - 'like a purple ball' - under her tongue. She needed hospital treatment after the incident - but still wants her lip pierced.