"Thirty days it took me to get over the shingles, and according to Donald Rumsfeld, that's right on schedule," said Dave, whose shoes had been filled by 14 substitute guest hosts and reruns.
He also paid tribute to his dermatologist, Richard Granstein of Manhattan, who was presented with a bouquet of flowers by two nurses -- actually models named Nadine and Andrea. (Letterman, 55, also had the "nurses" escort him back to the stage in February 2000, when he returned to work from open-heart surgery.)
Turning serious, not about his shingles but about his late friend and fellow comedian George Miller, 61, who died of leukemia last month, Letterman added a few words of tribute.
All told, Miller had made 56 appearances on Dave's various shows.
But it was back to shingles with guest Billy Crystal, who, it so happens, has also suffered with the condition.
"It hurt so much I was Michael Jackson-crazy," said Letterman.
Then, to the tune of "That's What Friends Are For," a video montage highlighted those who stood in for Letterman this past month.
And, perhaps most moving of all, Dave held up some of the get-well drawings he received from a kindergarten class in Bowie, Md.
JOSH & FERGIE: ROCKED BY SCANDAL
Did he cheat with a stripper?
Married less than a year, the couple denies an Atlanta woman’s claims that she and Josh had a fling
Note that this week’s cover of PEOPLE may differ regionally
