
I had similar happen when taking my dogs away on holiday. And I don't ever throw sticks. I had taken the dogs to Slapton Sands for the day. For anyone who doesn't know Devon, it is a pebble beach.
We had a great day out, but, that evening, back at the bungalow I'd hired, my youngest Beardie girl yawned - and started screaming. I couldn't see anything wrong, and it was only next time that she yawned, I saw inside her mouth was full of swollen haematomas.
Luckily, I found a specialist dental vet near Torquay. When he opened her mouth wide she screamed (but didn't go for him!) and she had - way down in her throat, two noticeable injuries, as if she had been pierced by something. To this day I haven't a clue how or when it happened, but have always wondered if she ran onto a stick or branch. I didn't see either, but don't know what else could have made such a mess.
I hope your girl soon recovers.