well, she WILL be sad about the mark, if you keep mentioning it.
and no, i didn't take her to the doctor. i asked her mama and yeh yeh how she reacted after the fall... did she vomit? did she squeal when she cried? did she seem disoriented? did she have a difficult time balancing? the answers to all of these questions were "no", so she seems ok. IF the answers to ANY of the questions had been "yes" then i would have taken her to the doctor immediately.
as i said, ALL children fall. it's part of how they learn. you CANNOT and SHOULD NOT try to stop it from happening (unless, of course, you see VERY dangerous behaviour).
you are not a bad mother because your child fell down.