frilled sick?

[echo2oo2]

Frank our frilled dragon had a bunch of parasites a few months ago, and he was doing good afterwords. then about 2 weeks later he had a swolen back leg and we went back to the vet and they couldnt find a reason for the swelling. and they have kept trying to get us to come back but we have already spent over 600 bucks on tests and meds for the parasites. the swelling has gone away and he looks like he use to. but hes been not eating much and rather lathargic the past month. some days he will go running all over his tank and others he just hangs out under his heat light. we want him to be 100% healthy but we cant aford to keep shelling out money at the vet. any ideas?