The results were remarkable. After the blistering sessions in which couples argued, their wounds took, on average, a full day longer to heal than after the sessions in which the couples discussed something pleasant. Among couples who exhibited especially high levels of hostility while bickering, the wounds took a full two days longer to heal than those of couples who had showed less animosity while fighting.
via nytimes.com
I enjoy reading about these studies. We can now scientifically show that if you significant other has a blister, you can control their recovery time by controlling your animosity knob.
There is more of course, about 5 pages worth, Read the article if you want to explore it.