Let him rest and don't ride, the vet's visit can be hard and stressful for some horses. Let him recover from his emotions!
Vaccines can tire a lot horses. When mine is vaccinated, I let him rest for 2 or 3 days. If the check-up does not include vaccine, I let him in the field for one day or do a walk in hand.
If you need to ride him for any reason, do something really simple. It is a good idea to go for a little walk. If the vet made a vaccine to your horse, if I remember well, you cannot ride for the rest of the day, you have to wait to day after!
The best is to let him relax and rest. You can give him a good grooming, walk him a little bit outside in hand so he can enjoy the fresh air and grass :)
I guess the best is to let him rest for the day.