There is a contingent of people who believe their Lupus is associated with metal fillings in their teeth. No conclusive scientific evidence, but I would rather "be safe than sorry".
If you must try a piercing, you might want to make sure the jewelry you wear is either surgical stainless or 14K (or more) gold. These are much less likely to cause reactions than a lot of the less pure 'pot' metals with nickel, etc in the mix.
Lynnwood, Lupus & Sjogren's Moderator, Dx: 2002DIAGNOSING LUPUS & HW's LUPUS 101
"Life is far too important to be taken seriously." - Oscar Wilde