At this point in time since you are a military veteran and currently in possession of your DoVA official/final ratings, you will need to complete a VA Form 21-0958 DoVA Notice of Disagreement (NOD) immediately to ensure that you don't miss the one-year deadline requirement to officially file a VA appeal for disability compensation.
As such, upon completion of the aforementioned VA form, please ensure to attach any/all medical evidence and/or medical documentation to the NOD then forward it to the designated DoVA Claims Intake Center (e.g., either PO Box 5235, Newman, GA 30271-0020 or PO Box 5235, Janesville, WI 53547-5235; dependent upon your state of legal residence) via USPS certified mail (with or without the return receipt option).
Thus, I quite often comment that "possessing well-informed knowledge is truly a powerful equalizer."
Best Wishes!