I am so sorry for the sad news. Oral tumours are horrible and grow so fast. It is very difficult to know when its time as the hedgehogs never seem to be in pain and continue to eat and act like normal. The tumour can take up half their mouth and they still seem happy and bright eyed.
I can't help much on when to know it's time only to say "better an hour too soon than a minute too late".
I can't help much on when to know it's time only to say "better an hour too soon than a minute too late".