GOOD NEWS -- He beat up Wanderlei Silva at Bellator 206 last month.

BAD NEWS -- He broke his left hand while punching the dude in the head!

It was the 4th meeting between the two -- and Rampage was able to even the series with a 2nd round TKO.

"I feel good," 40-year-old Rampage told TMZ Sports ... "I needed that."

Rampage revealed he was injured going into the fight -- "I hurt my right hand in my last sparring" -- but says he jacked up his other fist while inside the cage.

"I ended up fracturing my left hand on Silva's head."

Rampage showed us his hands -- you can see his left one is super swollen. He said he went to a hand specialist the very next day.