Allergies? Melanoma?

I'm currently writing this entry in the waiting area of the Dermatology Department in Hopitaux Universitaires de Geneve. I am here on the advice of one of my flatmates who is in intern here over summer. She saw my brown streak on my fingernail on Saturday, and said that I should get it checked out, as the worst thing it could be is a melanoma, particular since it is growing wider all the time. I've had it for about four years now, and have never gotten it checked out, since it was much thinner in the past and looked fairly benign, but not it is almost hal fo my finger nail. I am also here as since my time in the sun on Saturday afternoon, my face was swelled up like crazy, and I actually look like a different person with my round cheeks and puffy eyelids which make my eyes look very small. This has happened to me twice before, once last time I went to Geneva and went hiking in the Jura with my supervisor, and the other time I was in Cairns on a tour of the Far North with my boyfriend. I went to see a CERN nurse this morning, who thought it was a sun allergy, and so gave me cream and an allergy pill to take for the swelling, but I kind of actually want to know what it is so I can avoid it in the future. I find it quite strange, since I spend heaps of time in the sun at home in Melbourne, and it has never happened to me there. Let's see what they say...