I can buy DJI Care from the dji.com site.

The question I have will I be able to use DJI Care in sweden?

Do I need to buy DJI Care from a swedish retailer to make it work in Sweden?

You can just go to the store and make sure you have the right country selected.

(top right of the store)

This is stated on the site.
3、Does DJI Care Refresh support international coverage?
No, at the moment, DJI Care Refresh only works in the country or region that you chose when purchasing the service plan. DJI Care Refresh and the corresponding product must be purchased from the same country or region.

https://store.dji.com/product/dji-care-refresh-mavic-air-2

Hi there, you may refer to Montfrooij's reply or check this link: https://www.dji.com/se/service/djicare-refresh/info#faq to know more information about the DJI care refresh. Should you encounter any further difficulties, please feel free to let me know.