A week ago, had fever blisters inside right nostril. Painful. Healed. Head cold came on suddenly on Friday morn, moved down into my chest leading to asthma symptoms by Saturday morn. Now have start of fever blisters inside my left nostril and on my upper lip. By phone, pulmonologist prescribed breathing treatments with xopenex (which I know to do) 20 mg steroids 1xpd for a week until I can see doc, and five day supply of z-pak antibiotics. I have not started antibiotics because I do not do well with them. Questions are: what causes fever blisters and so many? Is it necessary to use antibiotics? Are there other recommendations for treatment? Thank you!