Zarvan Zeshan

Your painting looked deep and luminous while the paint was still wet. Two days later, half of it has gone chalky. The darks are flat, the values have collapsed, and the surface looks like two different paintings stitched together. You have not ruined it. What you are looking at has a name, and it has a fix. Several fixes, actually, each with different consequences. This is sinking in. It is one of the most common problems in oil painting, and nearly every painter encounters it eventually.