Can stress cause facial paralysis and/or bells palsy ?

Not per se. The cause of Bell's palsy cannot be established in many cases. It generally follows viral infection. For info: https://www.mayoclinic.org/diseases-conditions/bells-palsy/symptoms-causes/syc-20370028

Medical studies have shown that Bell's Palsy is often caused by herpes simplex, and a complex facial paralysis syndrome called Ramsey Hunt Syndrome is caused by herpes zoster. Emotional stress has no causative pathology related to the facial nerve.