Hi, this is Dr. Gabby,
I would do the three months of stall rest and skip pony finals. The main reason is we know if he has to jump at pony finals there is a good chance he will make the injury worse.
I did that to my own horse (very dumb) and then she had to have surgery. I decided I needed to go to a show when she was slightly off and sensitive on check ligament palpation. After the show she had a severe check ligament tear and then the suspensory tore because of the damage and inflammation of the check ligament.
My colleuge who is an equine surgeon did the surgery and told me she may never be sound again.
Then she had stall rest for a year! After a year of stall rest there as a 6 month slow rehab.
Last week my friend too a lame horse to HITS jumping and now that horse is on 3 months no turn out for check ligament.
So it is not worth it.
I know you usually can only take the pony you qualified on but could you call show management and ask if you can take another pony?
Is one show really worth the risk? And you can take the gas and hotel and meal money you would have spent at the show and use that towards healing him. Or save it for qualifying next year.
I know if it is after the closing date you can not get the entry fee back.
Does that make sense?
Your vet is right in that you can try it but you could also seriously injure a fantastic talented pony.