Is frey's syndrome familial?

No. Frey's syndrome is also called auriculotemporal nerve syndrome. This occurs after damage to this nerve in the face from trauma (birth trauma, gun shot, surgery, etc) and as the nerve "regrows" it goes to the surface rather than to the salivary gland. When a person eats something and salivates, the develop a red, non-itchy rash along the face where the nerve is. It's not familial.