Not only is the hand in extreme perspective with the fingers coming out
at you - but the arm is as well. Proportionaly, the hand looks WAY too big, it's bigger than the head. But no, it's not, the hand is closer to your eye than the head is, so the hand will appear larger than the head. When faced with such a challenge, it's best to use your pencil and measure rather than eyeball it, because it's difficult to guess how large to make the hand. So on your subject, measure the hand against the rest of the body that is visible so you can get the proper proportions down for this drawing.