For a quick sequence where we see a close up of Bugs' hands massaging Elmer's scalp to the notes of a short piano solo in the opera, they are deliberately drawn with five fingers for the sequence so they can believably follow the tune. See more
How about a nice, close shave? / Teach your whiskers to behave. / Lots of lather, lots of soap. / Please hold still, don't be a dope. / Now we're ready for the scraping / There's no use to try escaping. / Yell and scream and rant and rave. / It's no use, you need a shave!
[as Bugs slashes him with razor
Ooh! Ouch! Ouch! Ow! Ooh! Ooh! Ouch!
There, you're nice and clean / Although your face looks like it might have gone through a ma-chine.