Squamous cell carcinoma of the skin most often occurs on sun-exposed skin, such as your scalp, the backs of your hands, your ears or your lips. But it can occur anywhere on your body, including inside your mouth, the bottoms of your feet and on your genitals. Signs and symptoms of squamous cell carcinoma of the skin include: 
A firm, red nodule
A flat sore with a scaly crust
A new sore or raised area on an old scar or ulcer
A rough, scaly patch on your lip that may evolve to an open sore
A red sore or rough patch inside your mouth
A red, raised patch or wartlike sore on or in the anus or on your genitals
