On unaffected areas. Tattoos always have some risks and dangers. In patients with raynaud's phenomenon, there are repeated episodes of inadequate blood flow to the hands and feet, plus some other areas. Any injury to affected areas may take longer to heal, may be at higher risk for infection, and can have a harder time clearing any infection. It seems wise not to tattoo any areas affected by raynaud's phenomenon.
Maybe. An accurate answer would depend on the severity of the disease, other co-morbid diseases and any immunosuppressive medications for these other diseases. If the raynaud's is mild, without other severe diseases like scleroderma and you are not on immunosuppressive medications than the risk is similar to those without raynaud's.