Panel 1: We start out with Mike looking out the window; he tells Lawrence, who's putting his weight on his bad leg, that his mother's here.
Panel 2: Since it's been about four days since his leg got broken, he's fairly excited to see someone he foolishly hopes will care; his happily yelling "Mom! Mom!" is sort of pathetic in a way.
Panel 3: She calls him by name as she starts to hug him; since she looks what would happen if Little Orphan Annie and Ronald McDonald had a baby, he's understandably reticent.
Panel 4: He asks if that's her in there; this is supposed to indicate that she has indeed changed so much, her own son doesn't know her.
Summary: Where it falls down, of course, is that he should be saying "Why do you look like the clown on the lamp in my bedroom?" That's because she became a different kind of ugly.