Low. If the squamous cell cancer is truly on the skin of your face, then the risk is low for small lesions. If the squamous cell cancer is on the lining of your mouth or oral/nasal passages, then the risk of spreading to the lymph nodes is much higher.
Overall low, but. Of squamous cell cancers from the skin, tumors arising on the face do have higher rates of spread than ones that arise on the body.
Low. Squamous cell carcinomas of the skin are slow to spread to the lymph nodes in early stages. However, that is not a reason to ignore a skin lesion that may be squamous cell carcinoma.
5% In general 5%, could be higher or lower based on the specific features and location of the primary.