A tattoo in a dream often represents permanence -- a decision, belief, or identity you're marking as fixed and unlikely to change. Getting a new tattoo can reflect a form of self-expression you're ready to commit to, while regretting one may point to an old choice that no longer fits who you are.
Refuse the Moon in Cancer or Scorpio for marriages, unless it be in marrying of widows. - William Lilly (1602.-1681.)