Razor blades
I've mostly always used wilkinson swords disposable razors.
Last year i bought some SuperMax3 (3 blades) that were a new product on offer. Buy 4 + 4 free in the packet........I have been using them since the winter, and thought i had a coldsaw round my mouth from the cold, which the razors were re-irritating when i shaved, although i've never had coldsores b4. I've had to keep putting on vaseline to sooth the sore!
Anyway, last week it dawned on me it might be the SM3's that are the problem, so switched back to WS razors. The result has been no more irritation, and healthy skin around my mouth.
I think the 3--blade system is a con. They argue a smoother shave, due to a smoother shaving surface etc. but i cut myself with them just as much as i do with 2 blades, if not more, which i see as being due to the bigger razor blade covered area.
SM3's also have a "nature strip" made up of the healing, anti-bacterial, anti-microbrial tea-tree oil. I don't think i'm allergic to it, as have used TTO in other H&B products.
Lesson learnt - stick to establishedbrands like WS, and when you find a product you're happy with, if it ain't broke........