There are several ways, depending on your GM-ly inclinations, but this is a tricky problem. It's easier, in my experience, to punish a socially adept PC with Bad Stuff (paranoia and insults come naturally to the setting) than it is to reward a socially inept PC with Good Stuff.
First: Brute Force of Will
And I mean force of will on your part to bend over and find charitable interpretations of the character's statements. Dworkin might be immune to that sort of thing by now. Or it might be so outrageous that he assumes it's a bad joke and ignores it once. Or, since his origins are of Chaos, he might be having a moment where that's the right thing to say.
This, of course, is obvious, and it obviously has limits. If your concept of Dworkin is humorless and my interpretation of Chaos does not fit your game, a point buy should not override that. Moreover, as you've no doubt noticed, it gets stale. Quickly. But since the Stuff is to be bought off, maybe that's okay.
Second: Behind The Scenes, Directly
If it's important to you (or the player) that Good Stuff characters be charismatic and popular, you can convert some of the Good Stuff into social insight that you bestow to the player in some fashion or other. My personal preference would be directly, GM-to-Player and out of character, at least somewhat: "Before you get that question out, you realize that Dworkin's hunched back and twisted body might make him... especially sensitive to that remark."
I have also seen PCs set up with NPC helpers to provide the same sorts of advice, which worked well but depends on a receptive PC. This has the benefit that when the Stuff is bought off, the flow of advice stops. Maybe, if you're lucky, some of the advice will stick and you'll be left with a Zero Stuff character that acts appropriately close to Zero Stuff.
Third: The (Seen or Unseen) NPC Patron
Any number of NPCs (notably Benedict, Fiona, Random) can buffer the PC from at least some fall-out from his or her actions. If for some reason Benedict has some use for the character, a subtle or not to subtle word in the right ears can deflect a lot.
This also has the benefit that once Benedict has what he needs (i.e., the points are bought off) the protection ends and its open season.
Fourth: Some Guys Have All The Luck
Some folks are lucky and always manage to say the wrong thing at the right time, which is to say, when the person they've inadvertently offended simply aren't in the right position to respond or retaliate.
I will admit, this suffers from the same flaw as the first point, which is to say that it gets old very fast. It's very hard to maintain believability in my experience (I've never done so myself) but if this is short term, it may work, so I mention it.
Fifth: Encourage The Player To Make The Buy Now
(Pushing back against the question frame slightly.)
How you do this is up to you, but four points of Bad Stuff (in many games) isn't that much. It's not crippling. And in some ways, this is the ideal situation: Player gets shiny power (and the potential to really annoy people with) while you are relieved of the burden of having the universe treat this guy well.
Sixth: Accelerate Your Points Award Schedule... Just This Once
(Pushing back against the frame more firmly.)
This is self-explanatory.
(Pushing back against the frame entirely.)
Don't. Just don't. One assumes that the major NPCs, at least, are not blind fools and retain some agency. No points buy should be enough to bend your entire campaign out of shape. Leave them luck and whatever else Good Stuff gets them, start them with a cache of goodwill, but make clear it is not an inexhaustible resource. There are limits.
But in fairness, especially if this is going to change the way the game treats the PC, you do need to inform the player of this, and probably go out of your way to communicate when they just burned some of that resource. (So, it's similar to giving them advice before hand, except the timing is different-- tell them after.)