Wellllll, you know it's been a while since I've analyzed a Beatles song but I was listening to this gem the other day, and I gotta say, this is a fine example of how deft and agile Lennon could be on the guitar. He's doing things I wouldn't have picked up on if it wasn't for the fact that he benefited from an imbalance of levels between his amp and the amp of Mr Harrison.
In this otherwise well recorded version, we can hear basically every note that John is playing and he's playing some fantastic accompaniment to Paul's singing and rocking bass line.
If you don't already know, Paul nicked the bass line from a Chuck Berry song, "I'm Talkin Bout You" and is one of the main drivers of ISHST. The other is this great chugging thythm John is playing on his low E string which he accents by stabbing out offset E7 chords with a quarter-quarter-Eighth pattern or , down-down-up then shifting back to the low E string. He also changes this pattern up with another variation that George also mimics with a chmiey E7th of his own. (Right after "...sawwww her stannnnnding there..")
Anyway you get the picture.
But another great switch by John comes during the lead, where he stays quiet to let George shine through but he's now playing the Chuck Berry/McCartney line, barely audible, (Amazing!) and then goes back to playing full rhythm as George finishes up and Paul begins his last verse.
John finishes up the song with some more chugging rhythm variations and a good time was had by all but I think examples such as this, All My Loving, I Call Your Name and others show a surprising mastery of the role of rhythm guitar for someone who was still just a kid that didn't have formal lessons and actually only knew banjo chords when he started playing.
Just wanted to get this out of my brain since I had been thinking about it for about a week.