I've never showered at work...even though for some workplaces there was a shower. Just too much time and hassle for me.

But I always changed out of my cycling clothing, washed my face, wipe parts of me and dealt with my short hair (brushing it).
For certain, I ook worse with longer hair under helmet. I know I do, so I keep a short haircut: over half of my ear or whole ear shows, with the style I keep. I never worry...my hair grows fast.