I have cold sores on my lips and my mouth interior is puffy and red. It is hard to swallow and hurts. I have had Invisalign for eight weeks and this is the second time this had happened. I thought AI might be allergic to the plastic but if so then why only two flareups? I have used the cream Abreve (expensive ) on my cold sores and it really helps. I am glad to know I am not alone in the cold sore department. I can't use toothpase-it burns too much- so I brush with baking soda. On the plus side I am losing weight due to less frequest snacking.