This article is from the Piercing FAQ, by Anne Greenblatt with numerous contributions by others.
An abandoned piercing that has only shrunk or partially grown closed
can often be reopened using an insertion taper, even if the piercing
appears to be lost upon visual inspection. Reopening a shrunken or
partially closed piercing is far less traumatic and will take far less
time to heal than repiercing.
An abandoned piercing that has grown closed may be repierced after the
scar tissue has matured and softened, a process which may take a year
or more. However, since the skin will never be as strong as it was
originally, repiercing behind scar tissue will not insure a successful
piercing. The second piercing is usually made behind the scar tissue
from the initial piercing; piercing through the scar tissue can be
difficult and in some cases very painful.
 
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