Think we need a background story here to get a better picture of what is going on. what do you mean she is weak? why was she at the vet in the first place? etc....

No need to soak before a shed. Keep your humidity up to around 60%-70% and give her a water bowl she can soak in if she chooses to. If in fact she does have a rough shed you can soak or do whatever is needed after the fact.

The over-handling and soaking is most definitley stressing her out.