I broke my ankle at the 2008 AKC Agility National Championships. At the time, I thought it was a sprain. It sounds more dramatic than it was. I was just getting out of a car and stepped wrong.
I thought it was a sprain, so I ran anyway. The next weekend, I had a trial, and I ran all 3 days. The NEXT weekend I had another trial. I ran one day, and the ankle finally said, "ENOUGH!!" I wound up in the ER with a diagnosed ankle break and Grade 4 sprain.
My advice? Go to a doctor. Because I didn't go to the doctor (and because I am diabetic and they couldn't do surgery on my lower ankle), I run with a chronic sprained ankle to this day. If I had gone to the doc earlier, I might have had a better result. IDK for sure. But my ankle hurts almost constantly (even now as I write this). It's not a game stopper for me by any stretch. I wear two ankle braces when I run, and they help a lot.
So go to the doc and follow his orders. I lose entry fees all the time. It's part of the sport. You enter, but you get sick. You enter, but you have a family emergency. You enter, but your dog strains a muscle. It's a bit like gambling when you enter.
Some clubs return money when there is an injury, especially if you can prove it with a doctor's note. Contact the trial secretary and see what the club's rules are. Most clubs don't do this because so many people lie.
A sad but true fact.