Well, I'm sure it's happened to us all - where there's sheep there's maggots.
Anyway, I'm so glad you found Twiglet and she's ok.
I've got a few observations to make though, about maggot treatment and use of Crovect (Permethrin)
Like you've mentioned, heavy and repeated use of Crovect on wounds can cause depression - after all it is a nerve poison. I've found however, that after the initial application to kill the maggots, you can dilute the Crovect up to 10 x and it still prevents further fly strike and kills off any maggots you might have missed. In fact, if you don't have shears or kitchen scissors with you and discover a case of fly strike, then you can apply the diluted crovect over as much of the animal that's affected (and then some). Even without removing the wool it is really effective and you will find that in a short time all the maggots are dead. The advantage of using the diluted stuff is that in the case of extensive maggot attack you are not having to apply large amounts of undiluted permethrin and risk poisoning the sheep as well. But this dilution still kills the maggots and the sheep seems to perk up a lot sooner.
I usually dilute with diesel as I think the smell probably deters further fly attack. At first I was worried that this might irritate the damaged skin but it doesn't appear to, and like I say the animals are up and looking better in a matter of minutes as the maggots stop moving and die off. You can also dilute with liquid paraffin which I find equally effective, or probably cooking oil or similar. I find that using an oil, as opposed to water means it sticks to the fleece better and also helps keep the damaged skin flexible.
By the way, some years ago I mentioned diluting the Crovect with diesel and how effective it was. I was slagged off by someone who considered that the residual diesel in the fleece was putting the shearer at risk. I would consider that coming into contact with the undiluted nerve poison, ie Crovect, applied in some cases in copious amounts, could constitute a much greater hazard.