Well for me If I let my hair grow for a month or 2.. when I shave I will have red spots and bumps.
their visible before shaving as I buzz off with no guard.. I usually wash my head with Nizoral shampoo, and apply some cream a few days prior to going sly.. in 10 years it's always been the case..
after I shaved and take care of my dome.. no more spots or bumps..