Can my child get cancer?

So I woke up to find my 11 year old son laying on his stomach and sun bathing directly in the sun (where we live it reaches 12 UV and it’s pretty hot). I have health anxiety so I panicked and raised my voice at him and said did you use sunscreen at least and he was like “no just trying to get some vitamin D” and I gave him a lecture on how he could get cancer and he seemed unfazed. What should I do now? My child is olive skinned but don’t think it makes the difference because the sun doesn’t care who it fries. Should I take him to get monthly check ups in case he develops melanoma? I’m so worried rn and I hate myself for not stopping this in time and at least giving him sunscreen.