Sometimes this can be very easy to fix. More than likely the flap it'self is warped a bit. Take your heat gun and apply heat while bending the flap to align with the wing tip. I had to do this on an Ultrastick and this did the trick in a few seconds. Mine was very easy to fix. Just be careful to not get too much heat in just one area, or you could damage the covering. Keep moving it back and forth over the warped area until you are satisfied that it's aligned.

Hope this helps.