Erykah Badu -- Inked Up Bikini Babe

The late '90s were good to Erykah Badu -- she had a bunch of hits, starred in some flicks ... so maybe that's why she was rockin' her best 1998 henna tattoos in Miami on Thursday.

The 42-year-old mother of three debuted her latest highlighted hair-tastrophe and showed off her temporarily inked up limbs while hanging out in a bikini in South Beach.