How long did it take for your child to get over hand, foot, and mouth disease?

We're almost two weeks in with my fourteen month old, and new blisters are still showing up. Our pediatrician told us to expect 7-10 days for this to run its course, but that it could be a bit shorter or longer. I guess we're just in the "longer" camp, but no one else I've talked to has mentioned it lasting this long!