hi, and welcome!
as a preface, if you search the board for perfectionism, you'll probably find LOADS of great advice. everyone here is so amazing and they've been through a lot of this kind of stuff.
closer to home, we have big problems with perfectionism with our girl (nearly 6) and have had since she hit Pre-K last year. it whacked us between the eyes, seemingly out of nowhere and it is a BEAST to deal with, so all the sympathy in the world for you and your bean - it's a tough road.
a few questions come to mind: is this a new behaviour? does she only melt down with this one thing, or is it more generalized?
i ask because if it's only just beginning, it might be being fed by something you may be able to pinpoint, and it might be easier to manage if you can go after it from the source. we wound up having to review all of DD's activities as well as her school environment - and we're still fighting it every single day, even though she's now homeschooling and generally greatly improved.
talky stuff:
we have emphasized the importance of drafts. that took a while, but she's really behind it now. i got her some REALLY good erasers (those white plastic ones) and a variety of artists' pencils in varying hardnesses. (the harder the graphite, the lighter they mark - makes for easy erasing until you're pleased with the shape.) we also looked at a lot of artists' drafts online, and talked about writers' drafts and editing and all sorts of related stuff.
we have talked SO much with her about how much perfectionism holds her back. stops her from seeing what she's made of. stops her from soaring. she's been frustrated by her own limitations, sure, but then we bring back the concept of multiple drafts. we praise the process, rather than the product up the wazoo.
"i like how you really worked to get that part of your flower the way you imagined it." "i can see how hard you are working to get your ideas out on paper." that kind of thing.
we have talked ad nauseam about how mistakes grow the brain more than doing something right the first time. DD is still sceptical about mistakes being good for anything, but she is massively competitive and wants to have the BEST brain ever, sooooo... i totally use that fact against her when she's on the precipice of a meltdown. cool book, btw: Your Fantastic Elastic Brain: Bend It, Shape It" by Dr. JoAnn Deak - might be just right for your DD.
practical stuff:
a bit of background for this next idea... in double-harness with the perfectionism, DD5 has had a problem with self-harm (from all i've read, she is an extreme outlier in this, so while this is relevant to this practical thing we've started doing, let me reassure you that it's NOT typical!)
because her reactions are so harmful, it is essential she replaces the meltdown behaviour with something innocuous. we tried a few things like coins in the pocket to play with and a paperclip to twist (ouch, not that one!), but the one that has stuck is wearing a hair elastic every day as a "bracelet." instead of hurting herself, she can harmlessly snap the elastic instead whenever she's feeling that rush of perfectionistic adrenaline. it seems to give her enough time to be able to choose not to totally lose it, you know? we've noticed that it's much easier for her to refocus with that little fail-safe in place.
maybe some kind of replacement behaviour might also help your DD?
all the best!
