I certainly don't recommend it, but it depends where you're hit.
For example, on the cheek does hurt quite a lot (depending on the punch, but I'm going to assume it's someone who is very angry at you), but you might not even feel it till a while afterwards.
However, on the nose feels like the Moon itself has been ripped from the sky and landed on your face. In people like myself, it also acts like a Rage Button, cause whenever something hits my nose (hard, that is, not like a balloon or anything) it causes me to become incredibly violent.
I don't know about the chin, but I imagine it hurts like a ***** in your teeth. Especially if your tongue is between them at the time. Ouch.