A doctor can tell if your child has hand-foot-and-mouth disease by the symptoms you describe and by looking at the sores and blisters.
Roast the beets for 50 to 60 minutes. Cook the beets until tender, checking them by inserting a fork into the center of each beet. When the fork glides in easily, the beets are tender enough to remove from the oven.
For the roasted beets: Place the beets in a sheet of foil and place another sheet on top and create a seal around the beet. Roast the beets on a baking sheet until tender, 45 minutes to 1 hour. Cool the beets in their foil packet for a few minutes, and then rub off the skins using a paring knife if needed.