How many times has Froch been hurt before?

Nah I think it was more that Froch was stepping to the right then sort of leant over to the right to try and avoid the punch and it just knocked him off balance a bit.

Also as Achilles touched on there is a big difference between being hurt and being stunned.

I think in the Dirrell fight when he got hit with the 2 counter left hands he was temporarily stunned but the Taylor fight when he got put down he seemed to be hurt, it's always quite difficult to tell though.