I'm sorry this is happening to you. During one of my Aya ceremonies, I felt my face melting, but it passed rather quickly (I think), and it was probably a hallucinogenic side effect from drinking the medicine.

When you say that your face is puffing up, does it feel like a frog face? This is how I feel when I do Kambo, the frog medicine which works well with Ayahuasca.

I'm not sure what's going on with you during ceremony, but does it feel like it has meaning to it? Does the swelling of the face and loss of control over your fingers feel of Spiritual nature? Or does it feel more like an allergic reaction that "you're not supposed to have"? What does the shaman(s) say about it?