How to plot non-parametric data with multiple time points?


I analyzed some physiologic data (blood electrolyte levels etc) which was fairly skewed, so I used Kruskal-Wallis to test for differences between groups. I originally plotted the mean and SD, but I learned that plotting the median is more suitable with skewed data.
My question is, how should I plot the spread of my data? Do I plot the quartiles, the median plus/minus half of the interquartile range, the range of the data or something else?
From searching online box plots would be the best way to go, however, I am comparing four different groups in a graph with about 20 time points - so box plots would make the figure way too messy - so I am trying to pick one measure for the spread.

Thank you for your help!