Yes, if you have new and relevant evidence that supports your case, you can file a Supplemental Claim. You can also appeal to the U.S. Court of Appeals for Veterans Claims.
What do I need to consider if I want to present new evidence?
For more information on this, you can download VA Form 20 - 0995: Supplemental Claim PDF.
Will do. One more question, if VA schedules an exam for me, do I need to attend it?