Sometimes actors are required to endure a degree of pain for their art.
The best example is poor Andrew Sachs in 'Fawlty Towers' - the 'Gourmet Night' episode where Basil runs a spoon over his head before running it down his face and then hitting him with it. You can clearly hear the 'clack' is the spoon hits his teeth, and the 'clunk' as it hits his head.
When interviewed, Andrew Sachs said he did ask John Cleese to 'go easy', but Mr C replied that it was a one-off episode, not a six-week run, so obviously AS's requests for a soft touch were roundly ignored - which only added to the overall comic effect.
I remember watching Charlie Drake (ask your parents) who performed his own stunts on live TV and did actually loose conciousness with concusion during a particularly violent piece of action.
Similarly, in an episode of 'Z Cars', again, live TV, an actor actually died on set, and the cast had to carry on and leave him lying there until the transmission had finished.
Acting is a dangerous profession - Noel Coward was right Mrs Worthington!