Tom Arnold -- Roseanne Tattoo Was The Worst Mistake of My Life

Tom Arnold says tattooing Roseanne's face on his chest back in the day was the stupidest thing he's ever done -- this from a guy who once did a film called "Homo Erectus."

Arnold tells TMZ ... he got the tat back in 1994 in a last ditch effort to save his marriage ... but obviously his plan failed, big time.

In fact, Tom says he had to suffer through a year-and-a-half of painful lasers to get rid of the ink knowing ... "I'd never have sex with anyone until I got that removed."

But Tom's affair with STUPID tattoos didn't end with Roseanne -- the actor says he got Chinese characters on his leg years ago, because he thought it meant "love of mankind."

Turns out ... he was wrong ... at least according to Tom's "Cradle 2 the Grave" co-star Jet Li ... who translated the tat ... and said it means something totally different and way more hilarious.

Check out the video -- pretty funny stuff.