LTSpice constraints on plots
It is possible to differentiate the steps in LTspice by Right-Clicking on the waveform's label (in the waveform window) and then adding @x to the trace's expression, where x is the step's number. For example, for .step param x 1 5 2, plotting V(out)@1 will plot V(out) for the value x=1 (first step), V(out)@1 => x=3 (2nd step), and V(out)@3 => x=5 (3rd step).

Alternately, you can Righ-Click in the waveform window and then on Select steps, where you will be presented a more graphical option of plotting the steps.

Note that you can't stop LTspice plotting all the steps when clicking on the node, but after you select the desired trace, it will stay plotted until overridden.

As a side note, in case you have stepped points and you have used .MEAS commands, the log file will have results for each step. With the log file still opened, you have theoption to plot the results with Righ-Click, then choose Plot .step'ed .meas data.