Can melanoma show up overnite?

No takes years: Melanoma dies not appear overnight.

Melanoma : Yes, a melanoma may "appear" over nite even though the cellular process has been underway for some time . Any mole that is changing size, color, shape or catches your attention should be evaluated by a dermatologist.

I suppose: Given that most people notice a new lesion one day, it would appear that it showed up over night. But in reality the patient just did not notice it before.

NO: It's been there; you just never noticed it.