My 9 Year Old Daughter Keeps Breaking Out With Blisters

My 9 year old daughter keeps breaking out with blisters in her right nostril, the first time was about June her pediatrician thought hand foot mouth, then maybe strep/staph, then possible first cold sores outbreak/herpes or whatever. He said if its that it will break out on lips every other time and it was just that bad that time BC of it being first one. However she keeps getting these outbreak and its same place every time. Her nostrils... do u have any idea what it might be?