My 4 yr old had the chicken pox vaccine. A week ago she developed a headache, high fever for 3 days with a cough and sore throat. The 2nd day red flat bumps appeared on her bottom and legs, she's had about 30 bumps. They swelled and had white heads but never turned in to blisters. The first ones are disappearing leaving a pink dot with no bump and new ones are appearing with white tops. Is this a mild case of chicken pox? If so how do I know when she's not contagious? If not what could this be? Thanks!!