What Causes Extreme Edematous On The Left Side Of The Vagina?

The left side of my vagina is extemely edematous, about 5 times bigger than the other side, at this point it is not painful, it is the whole left side of the vagina, it is very red in color, no warmth or tenderness. I have not had a fever. I am 36 years old, G3P3, I also have an IUD. I had some spotting early this week, lasting only a day. I have been married for 15 years, and do not sleep around. Is this something serious.