was forced to make a speedy exit from Highmark Stadium on Sunday night ... this after angry Bills fans continuously chucked snowballs at his head.

The Kansas City star was trying to celebrate the Chiefs' 27-24 divisional round win in Buffalo ... but when he got close to the crowd, Bills Mafia made him run for cover.

Video from the game's broadcast showed the flying objects came so often, Mahomes actually had to jet from the area while defending his head with his hand.

When he eventually got near a stadium tunnel to get into his locker room, he had to evade a few more snowballs too.

Fortunately for the quarterback, it didn't seem any tagged him too hard -- and he didn't seem too annoyed by the situation either, wearing a big smile nearly the entire time.

Patrick Mahomes was dodging snowballs tryna get off the field 😳

But, one of his teammates, Drue Tranquill, certainly appeared to be more than bothered by the matter.

The KC linebacker wrote on his X page that he almost threw a snowball of his own at a fan who heaved one his way ... before he fired off a jab at Buffalo's diehards.

I caught the snowball. If it didn’t break in my hand, it was getting launched right back at him.

We’d beat them in a snowball fight too.

Truth is, my four year old throws a meaner snowball than . 🔥🔥🔥

"Truth is," Tranquill said, "my four year old throws a meaner snowball than #BillsMafia."

While the Chiefs escaped Buffalo unharmed ... they might have to face a similar issue this weekend -- they're slated to Baltimore in the AFC Championship on Sunday ... where snow could certainly be a possibility.