Iphone 8 when i call someone they cant hear me very good

when i call someone they cant hear me very good, I can hear them just fine but sometimes they will say I sound like I’m under water. Using earbuds when calling seems to fix this. I have tested my microphone on Facetime and voice memos and it sounds perfectly fine. This only occurs when I am talking on the phone. Thank you and any advice is appreciated (this has been happening across multiple updates)