I used an artificial nail to my fingernail on a Sunday and by Wednesday, I noticed the nail was turning green but thought it was because the artificial nail was discolored by something like a marker. I removed the nails on Friday but two nail were green, one more than the other. I do recall feeling discomfort when applying the nail on Sunday as if the artificial nail was too tight on the nail but I didn't thing too much of it. If the nail is still greenish - is a bruise or a fungus?