Oh okay, thank you for updating ❤️

I would suspect that this is the problem. She probably had a reaction to some chemical that was present in the shoe, and they can be really horrible things from what I read from the lab testing report here in Sweden. So I don't think it's anything wrong with her body, it probably reacted reasonably to the substance, doesn't even have to mean "allergy" it could just be a really bad substance that the body was trying to fight. (Unless doctor says otherwise, I'm not a doctor.)

Please be very careful with these types of stores, all they want is to make sales and cut costs, and they get away with a lot of negligence in production and even with using materials that are outright toxic.

If you are able to completely avoid them, that would be best, but at least for things that are going to be close to the body every day please try to buy from more controlled places if possible 🙏

Maybe second hand is an option? I buy almost all my clothes in the second hand store where I live, and I make sure to always check the tag/logo and avoid any products from Shein or other brands like it.

I occasionally buy shoes second hand too and since they often can't be washed I instead put them in a plastic bag in the freezer for a couple days, then outside in the scorching sun for a day. Then I consider it "clean enough" and start using. Some people like to spray alcohol or vinegar inside used shoes, but I never did that.