Hi Isabel Rodríguez Busto,
Thanks for reaching out to Microsoft Community and posting your inquiry.
In cases of dirt or dusts inside the camera, kindly Contact Microsoft Support right away to get assistance from an advocate to help you out with the replacement options for the device.
If you're located outside the United States, you can check our Global Support Contact page; https://support.microsoft.com/help/4051701/.
Kind regards,
John Neil_J