My sim shaved himself. How long does it take for facial hair to grow back?

I made one of my Sims have full beard, but I let him shave it once because I wanted to see the animation and now he's been barefaced for over a week in game (I checked and I have hair growth enabled). I'm getting impatient, because he hasn't even gotten a stubble yet and he doesn't look himself without a beard.
I may have to go to CAS and give him his beard back. I wish it would grow back a bit faster, I hope it's not bugged.