I just accidentally pulled out, while playing, my cat's whisker entirely, follicle and all. I feel terribly as I know she is a kitten and whiskers are rooted deep in a place rich in nerves. I'm wondering if the whisker will grow back and if it will cause a lot of pain as it does regrow.
The short answer is that yes, they will grow back. Cats do regularly shed their whiskers and grow them back in time (reference). The thing is that if damage has been done to the root of the whisker, it may grow back in an irregular manner (reference). Wish for the best and by now I think the whisker should be back just fine.