I would not shave the dog. The coat insulates him from the heat (they do not sweat like we do) and it often does not grow back properly. He is likely to get sunburned as well. Keeping him combed would be good to git rid of any dead hair and inspect for more ticks and hotspots.
I found a nice article for you to share with your vet (from another vet)
Shaving your dog’s coat – should you or shouldn’t you? | Albert North Vet Clinic