I was visiting the site via the app and there was a fine answer which deserved, in my opinion, an upvote.
I have just been alerted (because of a drop in my rep points) that instead of upvoting I have downvoted for error: I touched the wrong part of the screen and didn't notice.
It was an error on my part, the answerer need not be penalized because of this. I cannot remove the downvote because the answer should be edited. What can be done in these cases?