The tan that is created by increased melanogenesis typically lasts for a few weeks or months, much longer than the tan that is caused by oxidation of existing melanin
People usually don’t claim to have a tan if they go back to their default skin color three days after their vacation ended, do they?
Yes, but if you read further it says:
People usually don’t claim to have a tan if they go back to their default skin color three days after their vacation ended, do they?