'Bad Girls Club' Erica Lynne -- Bloody Revenge on Sex Tape Partner

It's a celebrity sex tape TRAGEDY ... TMZ has learned a former "Bad Girls Club" star who filmed a XXX tape with her ex-BF has moved on ... and she's making the break-up official with the help of a tattoo artist.

Erica Lynne -- who raised hell on BGC Season 5 back in 2010 -- tells us she stupidly got her ex-lover's initials tatted on her arm back in the day ... thinking the relationship would last forever.

But after they split, Lynne says she got sick and tired of staring at the letters, which were inside a heart design ... so she's gonna fill the heart in with a leopard print design instead.