whisker turning black

by Anne R
(junction city ks)

I have a flame pt Siamese about 7 years of age and she started getting black spots on her lips which I read online to be very common with age but in the last month one of her whisker has started to turn black at the base and now the whole whisker is slowly changing about a quarter inch of it has turned black this week what could this be is it age or could we have a serious problem on our hands? She plays normal with our two other flame pts and she seems really happy, she was throwing up a lot but we changed the food to sensitive stomach dry food and we moved into a much larger place so they now have their own room and she has stopped throwing up if you have some info on this that would be great!