Friction to slow down vector based speed.

Newbie & Debugging Questions
#1 

     // Update point
		point.x = input.getMouseX();
		point.y = input.getMouseY();
		
		// Apply dampening
		speed.sub(dampening);
		
		// Move player
		if(range.intersects(MouseGhost.rect)) {
			// Update speed/direction
			speed = point.sub(pos).normalise().negate();
			
			pos.add(speed.scale(point.distance(pos)/100));
		}

Basically I’m checking if the mouse is inside the range of the tile. If so I want it to increase the speed. Then when the mouse leaves the range, I’d like it to continue on a bit. I figured if I subtracted the dampening vector from the speed vector it would slow down but that doesnt seem to do it. What am I doing wrong?