Unfortunately this is one of the main reasons the rule of not admitting a child until they are fever free for 24hrs without the use of meds is so common. In many cases the bigger illnesses start with a fever then move to show the other symptoms.

You need to decide based on how you feel as to whether you will work. I would lean to being closed and resting up versus opening for some but not all clients. Especially if they have to pay whether you are open or closed. I can see some people being upset that they are paying but have to stay home while others are paying and get care for the day.

I would send out a notice asap to all families that there is a case of hand foot and mouth, what to look out for in their children and that you are now showing signs so need to close for the day (or days).

However make sure you are not just panicking. This is one of the illnesses that mainly effect kids under age 5 and not so much adults, while some adults will catch it, it is quite rare.