Marilyn Manson -- I Got SLASHED OPEN During Fight in Switzerland

Marilyn Manson says he needed 24 STITCHES to reattach his ear to his head ... after he was GASHED UP in a bloody brawl in Switzerland.

The details surrounding the incident are sketchy at best ... with Manson tweeting, "I was hit by a glass table in a dangerous fight."

He added, "I was however, the victor but had to have 24 stitches to keep my ear from becoming Van Goth."

Manson -- who performed at St. Jakob's Hall in Basel earlier this week -- also posted a photo of his messed up earlobe (see below).

We're workin' on the details. Stay tuned ...