Say what you will about Tyson Fury ... but the dude is tough as nails -- battling through a massive gash over his eye to beat Otto Wallin on Saturday ... and then getting 50 STITCHES after the fight!
Check out Tyson's before and after pics ... Fury had TWO gashes on his face -- one on his eyebrow and one on his eye lid.
Wallin opened up the bigger gash with a flush shot to Tyson's face in the 2nd round of their heavyweight championship fight in Vegas on Saturday.