4month old with red rash with tiny raised bumps on stomach. started as small patch 2 days ago. had fever of 100 but not now. doesn't seem to hurt. ?

Rash: Unable to diagnose 100% but if is localized, non painful, raised and she is well, it is likely OK and safe to watch. There is a viral infection called rosella that is preceded by a high temperature for 2-3 days and the patient breaks out in a rash on her head and torso. It doesn't sound like this. Seek medical care if the rash changes or she is otherwise sick. All the best.