Iam having some issue in my i phone 7 plus ,when I try to open the setting in my mobile there is some horizontal and vertical lines are observed,it’s is apperaing only when I opening setting option

Iam having some issue in my i phone 7 plus ,when I try to open the setting in my mobile there is some horizontal and vertical lines are observed,it’s is apperaing only when I opening setting option ...its happening only when I open the setting apart from that such lines not visible in any other options