Hey, murad buddy I encounter the same thing happened on your device on my current iphone which is iphone 11. I bought it brand new and it was jut 6months old I haven’t dropped nor put too much pressure on it as far as I remember but that yellow spot appeared all of a sudden. What did apple say on you? Regarding with this matter? Because I have this problem now and my phone was already in their service center but they are still diagnosing if it is a built in device problem or if it is a human error.
Please reply ASAP 🥹