My Jack Russell Terrier has recently suffered from the effects of Lyme disease but still seems a bit lame. Could he still has some of the symptoms of the disease or is he just being lazy?

I am concerned that he is still sick...

Lyme does not go away. It sometimes lays dormant . Don't let anyone tell you otherwise .It doesn't get cured . It gets controlled . Once a dog has lyme, they can be reinfected every time exposed.

If your dog is still lethargic then ask the vet to renew the Doxycycline antibiotic prescription ;or at least ask for another C6 test to determine the number of antibodies in the dog. .
Also ;if your vet has knowledge of supplements ,ask about an immunity booster . We give our dogs one that contains astragalus .
It does not cure the dog ;but we think it helps prevent future infection.