Nice job keeping the shadows clean, I agree with anon that different hues in the shadows don't make sense if you don't have multiple light sources, but you heavily imply there are multiple light sources, so I'm just going to try and construct where exactly the light is supposed to be with lines. We're going to start with the head and make our way down.
Your only defined highlight is on the upper part of the right side of his head. This tells me that light source at minimum must be in line with his shoulders. Immediately however I am greated by the fact that the shadows that his sphere shaped head cast on itself is in the lower fifth of the head. This implies that the light must be signing on him pretty severely from his right side and from his front, not directly over his shoulders.
Next and biggest contradiction we run into is the shadow his head casts on his shoulder. This doesn't match up with the head whatsoever. The shadow begins on his right shoulder at an impossible angle if the highlight is to be held true, the blue line marks where the shadow interacts with the head, in order to be in the shadow, that blue line must meet *somewhere* in the shadows of the sphere of the head, either on the visible side of the the start of the shadows or some other side of the sphere that has the line marking the beginning of shadows. You imply here that the light is coming far more over his head than the highlight implies, this gets even worse however, when we get to the left shoulder. The highlights on the head imply that light is coming from the upper right and is going into the lower left. Therefore, if the head is casting a shadow on the body, the shadow cast on the shoulders should be to the lower left of the rest of the head. Where the shadow ends on the left shoulder/upper neck implies that that the light is coming from the upper left, and is washing downwards to the lower right, this is in direct conflict with the head. If there are supposed to be two light sources, there should be two shadows on the shoulders, if there is only supposed to be one, you need to be consistent.
The next most egregrious is the wrist resting on the opposite arm. The shadows imply that light is coming straight down. If this is the case, and his left arm is going from the front of the right arm, over the top, and under the upper right arm, the left arm *must* be casting some sort of shadow on the lower arm, it should also be casting a shadows on the chest as well unless his arms are being held multiple inches in front of him as opposed to gentle wresting on his chest as almost every single person who folds there arms do unless they're doing russian kicks in a squat.
With the left arm, the light goes from imply it is coming straight down to instead appear to be going from almost the direct right of the character. This is further reflected in the silhouette you put behind him, which implies that the light is coming directly parrallel on the horizontal plane (i.e. the plane that makes up the floor and ceiling) and barely offset to the right of the median plane (imagine a flat rectangle cutting him in half symmetrically from the front to back) this barely lines up with what you are doing on the upper left arm and the silhouette. but I could buy these as being consistent if you just made the shade on the upper arm small as the silhouette.
Next problem is the super dark shadow on the neck and the clothing. These technically match up, but imply the lighting is coming directly from above, this obviously clashes with the shading on the head, which again, imples it is coming from the upper right.
I assume, though am not confident, you were trying to imply two light sources, one that's casting the silhouette perfectly, and one that is coming from the upper right. If this was the case, there needs to be shadows interacting with shadows and highlights interacting with highlights and all other sorts of garbage.
To avoid this problem in the future, choose one point where you want the light to be, any point, all lines come radially from that point and will make it easier to figure out where shadows are as far as the "two dimension" that your flat drawing implies, to take care of the third one, you'll need to capture in your mind whether the light is front, next to, or behind the subject, once chosen, stay consistent. The closer the light is to be parallel to the subject, the more details in the lighting will show, the more difficult it will get.
Much better than the original mind you, but you really need to decide on 1. how many lights are present, and 2. where that light (or lights) is.
I apologize if this didn't make sense, it's a bit hard to explain verbally.