I doubt that just dehydration would cause her to get skinny. They store fat in their tails for times when they need it and if their tails are shrinking there is something going on. yes, silkworms are good for your leo but remember if there are parasites at work, which it sounds like there are, she will not get better, no matter what you feed her, until she is medicated. Force feeding is risky and can be dangerous so be careful when doing this and try to get her to the vet asap.
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0.1 Bearded dragon
0.1 mexican kingsnake
1.0.2 Leopard Gecko's
0.0.1 Rose Hair Tarantula
1.0 BTS
0.0.1 Reverse Okeetee Corn
0.1 Bullmastiff
4.1 Cats