What Causes Red Blisters Above The Lip?

I get red spot/blisters over my lips area (moustache area) very ofter sometime within a month or two. Generally it happens after i get common cold. I get cold due to allergy. But these red blisters are hurting.. they look like very bad and hurts when i wash my face or touch them.. somebody told me that these may be herpies. Are these curable.... what is the treatment?