Now, a poem you might consider for one of your ailments:
In Tennessee I Found a Firefly
Flashing in the grass; the mouth of a spider clung
to the dark of it: the legs of the spider
held the tucked wings close,
held the abdomen still in the midst of calling
with thrusts of phosphorescent light—
When I am tired of being human, I try to remember
the two stuck together like burrs. I try to place them
central in my mind where everything else must
surround them, must see the burr and the barb of them.
There is courtship, and there is hunger. I suppose
there are grips from which even angels cannot fly.
Even imagined ones. Luciferin, luciferase.
When I am tired of only touching,
I have my mouth to try to tell you
what, in your arms, is not erased.
Let's say I am participating in the event. Say I read this poem on The Poetry Daily site and think maybe it might heal a thing or two. I might make a label that reads: In Case of Ennui or Remedy for the Wooly Horribles or Color Capsules for the Beige or any way you want to approach the symptoms that this poem can help alleviate. I then print the poem in such a way as to be able to nicely fit into the bottle (little scrolls? I guess the length of poem and size of font and bottle will determine this). We'll add candy to the heart of it (a Hershey's kiss could be a good fit) and send it on its way.
The main thing to note is that you will be finding poems not writing them for this assignment. The idea is that National Poetry Month should bring more poetry into people's worlds and poetry that might send them to read a whole book by this poet or more poems overall.
Some sites that might help you find poems that might work for this assignment are the above Poetry Daily, and Verse Daily. Also, the Writers' Almanac site daily archives (click on any date to see some of the poems). Poets.org is loaded with options and even helps you out with themes.
Some poets to consider: Naomi Shihab Nye, Billy Collins, Robert Frost, Anne Sexton, Sylvia Plath, Wallace Stevens, William Carlos Williams, Mary Oliver, Adrienne Rich, Paul Guest, Mary Quade,
Poets who often use humor: Bob Hicok, Eliot Khalil Wilson, Joe Wenderoth, Andrew Hudgins, Erica Bernheim,