Panel 2: He wants to know what the problem is with one little wrinkle.
Panel 3: Her response is to rant about how, since the life she leads (as opposed to her poor diet and negative attitude) has aged her before her time, she'll be covered in lines in about a couple of weeks.
Panel 4: He then responds with an insenstive non-sequitur, as indicated by the fact that he has his back turned to her, about always being able to read between them. If he'd delivered his subpar pun to her face, it would be a hamfisted attempt to be sweet. Since he didn't, he clearly indicates he doesn't give a rodent's hindquarters about her feelings.
Hypothesis: Lynn is showing us that not only was John a big meanie who 'forced' Elly to do the housework her need to fill her time with dull, repetitve tasks would have made her do anyway, he was the insensitive clod who didn't care that she was aging prematurely as a result. He also didn't make a big deal over nothing either, the dirty rat. If she has to sweat and strain over self-created crises, he has to too.
ETA: I fully expect this to wrap up Saturday with a strip that has nothing to do with the original "Housework sucks" premise.