Does alopecia affects only the head ? What about facial hair, rest of body ?

I've heard it can affect facial hair as well, so it's possible it could affect all hair shafts and follicles.

Depending on the drug it can affect all body hair (including e.g. eyelashes).

There's a big difference in whether it affects the whole follicle or just the shafts. I'm pretty sure the hair grows back if the follicle is unaffected.

 

You should consult your oncologist to talk about palliative care for this side effect to your protocol.