How to plot "voltage drop" across a specific component in LTSpice?
Click on the left side of the component (cursor will be a red probe before, then turning gray), drag over the component to the right (cursor will be a black probe), then release the mouse button.

Now the graph shows something like V(N002,N003) which is the voltage between those nodes. If you know the node names you can also manually enter these expressions into the graph view, or move things around or do calculations there.