While twisting out the warp and holding firm, hit the aileron with hot air from a heat gun. Hold the warp out and let it cool. You may have to do it a couple of times, and may have to hold more than the twist out.

There is a lot that can be done with model airplane ailerons. The twist you mention wanting to take out is sometimes put in by others. If the tips of both ailerons are up, your wing will have washout, something many modelers like to have. Since our ailerons are held firm by servos, rigging them "out of alignment" works for other purposes than rotation on the roll axis.

In answer to your question about your ailerons, it depends.

If both ailerons have the same twist, and have their tips displaced upward, there is a strong probability that your model won't cause you any problems at all. If one aileron differs from the other, there is a probablility your model will show some kind of aerodynamic imbalance. The probability differs with the amount of difference in the two ailerons.

The original design of most of our models very probably assumes both ailerons will be identically shaped and not twisted. However, the amount that shows up with quality ARFs is so slight that most new modelers won't even identify it, and it won't matter.

What you should do however, is make sure that neither wing panel is warped. Do that first before judging the ailerons.