My dog has strong lymes has seen a vet and now has no appetite and fever.. how do I get him to eat,he drinks water regularly.

What are strong Lymes? I know dogs, I've had dogs all my life - and I've never heard this phrase.

I believe it means he has an active case of lymes disease.

The test result was "strong" on lymes test result.. pardon me for any misunderstanding.

The trick to restoring appetite may be in alleviating the fever. Are you able to take his temperature at home? A normal temp for dogs is 101-102 so don't be alarmed that if his temp is normal that you get what sounds like a high number. I would suggest that you take his temp and call your vet if it is elevated. Ask what you can safely give him. DO NOT give any human drugs without checking with your veterinarian first, they can be dangerous to liver and kidneys. And, if I am assuming correctly the antibiotic that was likely prescribed was Doxycycline. This drug can cause digestive upset, the reason for being given with or after a meal is to decrease the risk of vomiting or diarrhea.
If his temp is normal try something easy on the stomach like boiled chicken and rice or boiled hamburger and rice, drain off the fat in the broth before feeding it to him, you could brown the hamburger but boiling and draining gets rid of more of the fat which is difficult for the dogs body to process.
If you are still unable to get him to eat you may need to call your vet and get him a prescription diet that is higher in calories than most foods.
If you are able to get him to eat and he is taking his meds but has vomiting and diarrhea call your vet, to see if there is something else he can prescribe.