Hand foot and mouth

eswany1

I'm thinking my 3 year old son has hand foot and mouth big sores on this tongue smaller sores on inside of cheeks on and off fever and started to get light red spots on his feet. If it's hand foot and mouth how long is it contagious I also have an 8month old she has no signs of it. I just noticed this today when his tongue was sticking out of his mouth. I feel awful! Is there anything I can do