How to cure hand foot mouth disease?

Self heals over time. Hfm is a collection of symptoms related to infection by strains of an intestinal virus.It runs its course producing a variety of blisters in various locations before resolving as the body fights it off. The main problem with the disorder is the chance of dehydration from poor fluid intake. Comfort measures & a focus on improving fluid intake are the best method of rx.
Time. Let it take it's course, it usually is over in about 10 days or so.