Vasovagal Anxiety Reaction
Vasovagal Anxiety Reaction, also known as "needle anxiety" or "needle allergy", is not uncommon for some people, before a piercing or injection of anesthesia.
They become pale and feel cold and clammy — some experience nausea and lightheadedness. This can progress to hypotension (abnormally low blood pressure) and bradycardia (a drop in pulse rate, generally to below 60 bpm).
In a clinical setting a doctor would pick up on this being likely and prescribe a small amount of sedative or tranquilizer as a premedicant. If it does happen, the client should first be put into a position where they have a clear airway in case of vomiting, and then the legs should be elevated to correct any effects of postural hypotension. Smelling salts can be used to awaken the person.
While this primarily applies to anesthetic-related procedures, it can also apply to pretty much all piercing procedures where a needle is involved.