So I checked out the original image to compare and I gotta say it makes this piece looks very disappointing. it's almost a totally identical recreation of a posterized version of the photo. You gotta try to take more liberties when it comes to photo studies and portraits, being too close to the source will only hurt the appeal of your artwork; since it's art you should aim to make it better than reality.

The main areas where your piece sticks out because of the box you formed around yourself is the clumped areas of colors, which looks a bit splotchy 1. because the lighting is so complex in the original photo, mimicking it looks like a mistake without dozens of layers of subtle gradation making your piece look like a color-fill-in chart and 2. the colors themselves are gross. Dark washed up browns and red tones, nothing is particularly exciting or eye-grabbing in the composition. It also hurts the kiss marks which look about as dull as the skin and the beard looks like a dirt smudge because it's next to an equally yucky brown.

It looks clear you color picked specific areas of the photo and laid them back down in the same spot hoping for visual cohesion. If you're using photoshop, trying playing with the curves and color balance adjustments after laying down the base coat for a more aesthetically pleasing combination.