Augmentin antibiotic

My son, who is 22 months old, had an accident last Friday and got a deep-cut lip and scratches on his mouth. We went to emergency, and the attending doctor prescribed him Augmentin.

It's now his 3rd day of taking the antibiotic. However, we just noticed that he's getting rashes all over his body and face. Not sure if this is caused by Augmentin. Anyone here whose child experienced the same? How long did it take to clear their rashes? Thanks.