Usher's squabble with Chris Brown isn't going to affect his performance later tonight in Las Vegas -- because the guy's taking the stage regardless ... TMZ has learned.

Sources with direct knowledge tell us Usher -- who's currently scheduled as the headliner for Saturday's "Lover & Friends" music festival -- will take the stage as planned ... meaning, the show will, in fact, go on despite what happened earlier this morning with CB and co.

We're told that Usher was, indeed, injured during the brouhaha at the skating rink ... and that his nose and face are kinda jacked up right now. And yet -- our sources assure us he's going to power through and put on a good show. He may, however, be covering up a bit.

In other words ... be on the lookout for him wearing sunglasses of some sort tonight, and perhaps rocking some fresh battle scars that might pop out through any stage makeup.

As for Chris -- who was also in the lineup as one of the big acts slated to perform -- we're told it's unclear if he'll do his set tonight. Chris hasn't said anything publicly as of Saturday.

There's more ... TMZ can confirm reporting by B. Scott, who said the drama appears to have stemmed from Chris' scrapped AMAs performance last year -- when he was set to do an MJ tribute, only to claim he got the rug pulled out from under him last minute.

Our sources say that is, indeed, true -- and the reason he went after Teyana here is because we're told she was actually involved in the planning of that performance ... but something went awry before the day of. This makes sense, as it's been widely reported of late that TT has stepped into the role of a creative director lately for a number of artists/their shows.

Anyway, Chris clearly felt some type of way, and was confronting her -- which only escalated when she snubbed him. Not just that, but we're told Chris actually demanded Usher make her leave ... in addition to asking her to get out himself, seeing how it was his bday party.

We're told Usher refused, and the rest is history ... some of which you can see on video.

Time will tell, we suppose, if Chris will come out himself, or if he'll address this further. BTW, it looks like Teyana -- who was once a fierce CB defender -- has unfollowed him on IG.

We'll also keep our eyes peeled for anything Usher might have to say later today. Something tells us he just may talk about it.