Why does quality of my image changes drastically after editing it (and saving it as jpg with maximum quality ) in photoshop CC RAW. Everything looks great until I save the image. Comparison of the photo before and after saving/converting as jpg given below.
It appears most of what you are seeing is due to the use of high Clarity and Vibrance settings coupled with faster rendering options in the Lr preview window.
Depending on how you've got your viewing quality options selected, Lightroom may or may not be actually recomputing the raw data to produce the preview you see from within Lightroom. If you've got them set to render changes more quickly what you're seeing in Lr is more of an estimate of the effect of those settings rather than the actual effect on the image once it is exported and the settings are actually applied to the raw data.
Since the image in question was shot at ISO 4000 it can be assumed to be relatively noisy. Increasing Clarity and Vibrance increase microcontrast and thus tend to amplify noise.