Drainage
From BME Encyclopedia
In the process of healing, dead tissue (both from the area, and the corpses of cells sent to help heal) is thrown away and replaced with healed tissue. The body must have a channel for disposing of this waste to effectively heal.
While some drainage is normal, purulent drainage may be suggestive of an infection and should be reported to your piercer or tattoo artist immediately. If he or she feels an infection has indeed set in then one should consider consulting a licensed physician for possible antibiotic treatment.