there are a number of things that can create problems with an lscm unwrap, but usually it’s either that a seam isn’t connected somewhere, or there isn’t a seam where it should be. forgive the morbid reference, but think of it as skinning an animal. you want to make all your cuts in a way that the end result lays out flat. you don’t have to do it all in one piece though, and when a piece protrudes off of the main shape, it’s good to make a seam right at the base, and then one running along the back, for example: a finger would have a seam right at the base joint, and another running from the first seam up to the tip of the finger. that way it will unwrap into a nice half capsule shape. so:
#1 check to see that all your seams are connected where they should be
#2 if they are, identify the trouble area and add additional seam/seams
#3 if it’s still not unwrapping well, either redo the seams, or look into ‘UV pinning’, or do my tutorial on manual unwrapping in my sig.