DS (3yo) fell in M&S yesterday and bumped his head. He had a slight bruise and the skin is a bit broken on his cheekbone and eyebrow where his glasses were hit. He cried quite a bit which is unusual for him but he's been ill so thought it was just compounding factors making him extra sad. He went to nursery today. Fell asleep in the car home from nursery and I let him sleep a bit (usually don't but, as I said, he's been a bit unwell (not contagious anymore before I get jumped on). He woke up and complained that his head hurts and that he can't see. The low lights were on in the room so instead of getting up to turn on the main lights, I used my phone torch to inspect his eye to see how it was.
When I shine the light in his eye, his pupils rapidly change from large to small and back to large and back to small over and over again. I've never seen it before. There's nothing at all about it that I can find on Google (I can find when they stay big, stay small, respond too slowly etc but nothing about changing constantly like this).
I'm on the phone to 111 but obviously they're insanely busy so asking here if anyone has seen this - will post a link to a video when I can get it sorted but it's hard to do and he doesn't like me shining a light in his eye (obviously).