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 ... as he was involved in an absolute war with Poatan -- which left him bloodied up following his fourth-round TKO loss.
He kept it real about how he's feeling on Tuesday ... saying, "Septoplasty is the worst surgery on the planet!"
Rountree even had a video recording of the entire operation -- and if you get queasy easily, make sure you finish your turkey sandwich before watching.
Despite the loss, Rountree's handling it all like a champ ... taking to Instagram to give Pereira his flowers and thank him for the opportunity.
He even had the likes of Conor McGregor commenting on his performance ... who said, "Absolutely incredible showing!"
Speedy recovery, KR!!