All the KX's I've seen (up to "00) had rubber mounts that attach the bar mounts to the upper triple clamp. These deform easily under pressure, not that I've ever looped out or anything. Also the top bar clamp was flimsy.
Loosen the nuts that stick out of the bottom of your upper triple clamp.
Wiggle the bars and see if they will return more to the center. If the rubber cones are really stressed, buy CR500 replacement rubber cones, much tougher and fit right in. Also check the top bar clamp for deformation.
Tweaking the actual handlebars back is different in each situation, have fun.
If you have a hitch ball on your bumper, that can be a inpromptu vise.