Dean Silva at the medical school is more than happy to welcome Martin back into the fold. He has faith in Martin's abilities and was just waiting for him to sort himself out. After experiencing this forgiveness, Martin becomes a follower of Silva and gives up all connection with Professor Gottlieb, who ratted him out for being rude.
Martin works hard and stays away from booze because he now feels he needs to be responsible as a married man. But he can't resist sneaking off from school to visit Leora in Wheatsylvania again. Leora's family disapproves (of course!) but that's how it is.
Martin threatens to take Leora with him back to medical school, which he can legally do because they are married. He demands that Mr. Tozer give Leora money to support herself while he (Martin) is finishing school. Basically, he's driving a much harder bargain than he did at first with the family. He says that if the Tozers don't give in, he'll take Leora away from them forever.
Martin moves Leora into a little apartment in Zenith and visits her on the weekends, since he spends every moment of his weekdays studying and working.
His final years of medical school pass in a blur.
When medical school ends, Martin and his fellow students go their separate ways. He now needs to do an internship, and when he's done that, he moves to Leora's hometown to set up a practice. He doesn't really want to, but Leora wants to be near her family.
Before he goes and does all that, though, Martin takes an internship at the Zenith General Hospital.