Ambre Solaire Sun Screen Milk

I was skiing last week and purchased the sunstick prior to my departure, after two days my lips started falling apart, so I carried on using the stick for the rest of the week - my lips remained chapped and sore. On my return to the UK I stopped using the stick for 48hrs and they started to get better, then for some reason I thought I would use it again and about 8hrs later they have started to break up and become sore again. This has never been a problem before and plan on contacting Boots and hope that they will offer some form of explanation and apology.