Two short stanzas, two very different ways of picturing illness. In the first, the speaker is physical and blunt: "I itch and pimple." The body is irritating, a little embarrassing, and the verb "pimple" turns a noun into something that happens to you, which makes it feel almost comic. The phrase "the morning of my disease" is odd too. Morning usually suggests a fresh start, so it hints that being ill is its own strange beginning, a new stretch of life with its own routines.
The second stanza shifts to a image. Sickness "came for me" like a visitor or an official, wearing "plain white gloves." Gloves suggest politeness, formality, even a servant or an undertaker, and they also suggest care taken not to touch anything directly. Illness becomes courteous and impersonal at once.
The mood is wry and unsettled. The speaker seems to hold fear at arm's length with dry understatement, and the title "Invalid" quietly plays on the word's other meaning: not valid, not counted.