If you are concerned then go get your CBC now and not next week - then you know if you have something to be concerned about or not. Is it possible that you kept checking the knick and that's what kept it bleeding? My sister got a tortilla chip up her gum and it bled for hours - she eventually went to her doctor and it took him forever to get it stopped - my sister does not have ITP. The only reason I went to an electric razor for legs is because I have 2 new knees and do not want to cut myself and maybe get an infection as it would go right to knee/s.
Again - if you are concerned get the CBC today or tomorrow. Let us know what your results are!
"Instead of wasting your time worrying about symptoms, just get it checked out" -Nieca Goldberg, MD