You could try splinting, that might keep the leaf alive. You can use things like wooden chop sticks, tongue depressors or popsicle sticks, tape them around the stem to hold it straight, and you could do the same on the leaf. Since the leaf is still green you have a chance to save it.
If you can't get it to stay straight, the leaf will most likely brown and die. You could wait to see if that happens but it's pretty unsightly as it is, so if you don't want to try splinting, just cut the leaf off at the base with a sharp serrated knife.
