Allergic reaction or heat rash?

Yesterday Joanna finally felt better. She has slept a lot. Her fever left. Praise the Lord! The only other concern was that she had little red bumps all over her.  It happened after lunch time.  I don't know if she's allergic to something. It could be anything.  She has rash on her face, neck, arm, and torso.  Poor little baby.  We think it's the food she ate but then what if it's something from the nursery or someone's perfume?  We don't know.  I am beginning to wonder if it's heat rash?  Those rash are still there on her as I look at her this morning. Anyway, we'll be paying attention for signs that may cause those rash.  We're thankful it isn't anything serious.