Vinegar will not improve and will only get worse. It comes from acetobacteria that are present in the air, and is caused by exposure of the finished beer to air. This bacteria actually uses oxygen to turn alcohol into vinegar, so while vinegar increases, the ABV will decrease. You can often but not always detect acetobacter by the tell-tale rubbery pancake-like "mother" that floats on the surface. If you don't see a mother right now, you might later.
Avoid prolonged exposure to air-space in your fermenters to avoid this in future. This batch might be lost. However, it might actually make some mighty tasty salad dressing!