iPhone 11 pro ear speaker grill

Hi was just wondering if anyone has a similar issue to me, so I decided to clean my speaker grill and before i started i noticed that if i hold the phone at a certain angle under light i get 3 lines at the top and bottom of the grill, you have to look under really bright light and at an angle but they are in the exact same place top and bottom. any idea what they are ? is it something behind the grill , or have i scratched it. Can't see how i would have as there are 3 identical lines with the same gaps at the top and bottom.