Don't know what was wrong with Chester this morning - either he had something caught in his mouth, had eaten something which had irritated his gum or Bentley had caught him with a claw whilst playing ... or maybe none of the above, some other issue. Anyway, he was gurning, flashing his tongue out at odd angles and pawing and clawing at his (closed) mouth. Quite a performance, but nothing like the performance we had trying to see if there was anything obvious we could resolve. Rolled him up in a big towel, laid him on his back on my lap, OH was there with the torch, I prised his mouth open, looked, couldn't see much, one paw came out of the towel, then a back foot, than another back foot, then the second front paw ... what a wriggly squiggly writhey slithey little boy he was!
Anyway, upshot was that there appeared to be nothing stuck in his mouth but there is a small patch of reddenned gum. Reckon he'd got some sort of minor damage and it was uncomfortable for him for a while. He's much calmer now, but still patting it occasionally. Still managing to eat and drink so I reckon he'll be OK!
Update
I think he may have been stung! He's a little swollen one side and I think that would account for his behaviour. Poor little chap, but he'll be OK in the morning.