Does it ever happen that a squamous cell skin cancer grow under skin without any sign?

Usually not. : However some skin cancer can look like moles or other common growths. It is best to be checked by your doctor or dermatologist once a year. More frequently if you have a history of skin cancer or it runs in the family.

Skin: A squamous cell skin cancer would be visible as a non healing , crusted, scaly , or bleeding red area on a typically sun exposed area.