You do not need to replace parts, just take off the back panel and use a q-tip to clean all of the condensation on the inside part of the camera lens. If necessary, you can also q-tip the camera. Just always make sure to not put too much pressure. Hope this helps!
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Step 4 on the [link|https://www.ifixit.com/Teardown/Huawei+P20+Pro+Teardown/104605|teardown] shows how to take off the back panel.
You do not need to replace parts, just take off the back panel and use a q-tip to clean all of the condensation on the inside part of the camera lens. If necessary, you can also q-tip the camera. Just always make sure to not put too much pressure. Hope this helps!