Bl**dy hell! It hurt! C172 flaps are painful. It knocked me over backwards and dazed, I sat on frozen grass wondering why there were more things flying now than there were a few minutes ago.
Where you really sensible or safe to fly after this incident? May be it was minor and had no nasty consequences but what if you had caused a serious injury?
Maybe I am over reacting but I think it was irresponsible to fly, especially with pax, after this.