allergy

Seems likely you are allergic to the metal of your jewellery.

The most common metal allergy is NICKEL.

Your piercer should be using Implant Grade Titanium or bioflex - if they have used steel of some kind, it almost certainly has nickel in it and that is making you react. Find a piercer who uses assured titanium jewellery (they should have a certificate from their supplier available) and get your jewellery changed out as soon as you can. In the meantime, take an anti-histamine!