allergic reaction to penicilin?

Ladies do any of you know what the symptoms are when a baby has an allergic reaction to penicilin??

My baby just finised a course of Augmentin on Monday but since Sunday he has this fine rash on parts of his body like his bum, chin and cheek. Its red patches with very fine bumps but doesnt seem to be itchy or sore.

Im just scared its connected to the penicilin.. any ideas?

xxx