swollen / inflamed flap of skin under tongue

Hi there,

Im 24, I have smoked for a year now, drank normally for a few years, I have noticed about a week ago that the little spikey flaps of skin that follow your vein under your tongue one of those is swollen/ inflamed reddy white and pianfull when eating and moving the tongue around. Its not an open sore, its not leaing anything its just swollen and dangely and sore. Just wondering what this is? Never had it before nothing wrong with the rest of the little flaps on the other side or the top or the bottom of this one. Just a little worried about it....I have gargled and used lysterine mouth wash every day, this eases the pain and takes a little bit of the nastyness out of it, but it doesnt actually go away..... please help? :)

thanks chloee