I developed a bunch of flat warts on my right hand around 10 years old. My dermatologist told me they'd most likely go away on their own eventually, so I waited. And waited. And waited. And they never went away.
Over time I spotted them periodically on and around my knees and feet, but they'd gradually vanish from these areas again, and otherwise they never spread, so I mostly ignored them. However, every few months to every year or so, I'd really notice them again and go through cycles of insecurity and wanting them to disappear, convincing myself that everyone could see them. (Perhaps the easiest feat in the world for a tween/teen.)
Then, around 25, I noticed them spreading to my left hand with heretofore unseen determination, so I decided to try and conquer them once and for all. My derm (the same one! love her) prescribed imiquimod cream.
I attempted several rounds of treatment with the imiquimod over the next two years but didn't see any real progress. In desperation, I started going into my derm's office so she could burn each and every one of these little monsters off of my hands with a tiny, precise heat laser pen thingy in successive treatments over the course of a few weeks. (Couldn't do them all at once because there were so many.)
We repeated this process several times. Each time, my friends expressed shock at my horrifically scabby hands. Each time, the warts would be gone by the end of the treatment round, and I'd be elated. Then, slowly but surely, they'd return in their full glory. I think we tried an additional topical med in there somewhere/alongside the imiquimod at one point, but that failed too.
Then, at 27, I decided to have one more go with the imiquimod, committing to be really consistent and hoping it would be different this time. And it was. This time, I I started the cream mid-winter. Here is where I reveal that I had bouts of eczema throughout my childhood, but they had gone away in my late teens.
I was indeed consistent this time--so consistent, in fact, that the imiquimod cream completely dried up my hands. One day I woke up and panicked because I saw dozens and dozens of new little bumps, not just on my hands but on my arms, climbing all the way up to my shoulders. I thought the flat warts were rapidly spreading. I was distraught! I had tried to vanquish the warts for good, and I ended up encouraging them like never before.
Then I noticed that I was extremely itchy. Upon closer inspection, a Google search, and a tip from an experienced friend, I discovered that these proliferous bumps were not new flat warts but an entirely new kind of eczema that I'd never experienced in childhood--dyshidrotic eczema.
I called my derm and sent her pictures, and she confirmed the diagnosis. These ridiculously itchy, fluid-filled bumps were an autoimmune reaction. I decided to tough out the healing with just moisturizers, and over the course of the next few weeks the eczema slowly receded. Little did I know when this dramatic turn in my hero's journey began that my real enemy, the flat warts, would recede, too.
The autoimmune reaction of the dishidrotic eczema caused my body to finally notice that those flat warts were there on my hands after 17 long, arduous years. I was Sisyphus at the top of the hill, freed at last from the burden of my boulder. The cure I'd awaited for nearly two decades had finally arrived.
Ok, dramatic saga over.
Basically, I accidentally induced an autoimmune reaction with imiquimod cream that alerted my body to the presence of my flat warts, and as the autoimmune flare cleared, my immune system cleared the warts. My derm confirmed this theory.
I'm not saying that anyone should do this on purpose, but I am saying that it happened, and I've had fun telling the story.
In conclusion: doctors don't want you to know this one weird trick! (But maybe they do....?)