Julie,
Did your vet instruct you to treat them once a week for two months? What dosage are you administering? The dosage for a PTS is 50mg/kg, so probably a little less than 25mg for the average PTS. I might be wrong, but I have heard you are suppose to treat nematodes(like hookworms)with panacur once a week for about three weeks. Are you making sure to clean up ALL of their feces? Hookworms are not actually killed with panacur, so if you are not cleaning up the feces, your skinks could be getting re-infected via ingestion. Hookworms can also re-infect your skinks by burrowing in their skin. Did you just get a fecal float at the vet, or did you also do a fecal smear? If you did not do a smear, they could also be infected with protozoa's which are not eliminated by panacur. If indeed they are infected with protozoa's, you can treat them with flagyl. You can hand feed to make sure they are eating. I find feeding fruit first stimulates their appetite, then you can try to get them to eat their veggies and greens. Make sure they have plenty of water. I hope this helps. Josh