Sunscreen

Patient: I timed myself and realised that if I stay in the sun with no sun cream on for 1 hour 20 minutes, I get a perfect tan with no burn. If I do the same with cream, I have to stay in the sun for much longer which gets boring. Is there anything wrong with using no cream to get the same tan as long as I don’t exceed my time limit and get burned? I can not find the answer to this anywhere. I hope you can help me.Thanks

Doctor: