I'm glad that you are taking him to the vets. I'm sorry that I can't tell you what's wrong with your dragon...but I'm not a vet.

Re: parasite medication...you need to know the weight of the lizard to determine the dosage....but IMHO its not wise to just give him a medication without knowing what parasite you are trying to kill or if he even has parasites.

I never used coconut shavings for subtrate or shreded news paper and moss...I'm afraid of the coconut shavings causing impaction and the same with the moss. I always used cypress mulch and in over 15 years if water dragon keeping I have never had an impaction.

I hope that you can get the problem solved.