Khalil Rountree is still feeling the effects of his loss to Alex Pereira ... as the 34-year-old revealed he's in "pure pain" after undergoing successful surgery on his nose following UFC 307.
The eighth-ranked light heavyweight went under the knife for a septoplasty on Monday -- which is a procedure that corrects a deviated septum.
It's not shocking Rountree needed some work done to his schnozz .