Tjodit,
I've never crashed on the road - yet - but I've had two bad mtb crashes. One I flipped over onto a boulder (dont' know how it tripped me up), which left a scar on my knee. The other was a wipe out on a scree hill so that would constitute road rash. Yes it hurt and yes it left a scar. Lesson learned: don't use hydrogen perioxide on road rash, and clean it out as soon as you can. It really hurts to clean gravel out of your rash after it's hardened and starting to scab (I rode 14 miles after I crashed). There was a good thread here on how to treat road rash complete with ingredients for a road rash kit. I saved it somewhere, I just can't find it now....