You can't unbend the limb and if you remove it, it will take about 5 years to regrow the size trunk you have now., You have a very pretty tree just the way it is and if you cut the branch off the tree will not look good. The way I fix distorted Crepe Myrtle trunks is to cut them off at the ground level with the ground in the Winter, and regrow new stems. The second year pick 8 stems and the 3 year leave only 5 and on the fifth year only 3 adult stems. Each time I pick the very best stratest stem and leave for the next year. In 5 years you will have a good Crepe Myrtle.