Multiple canker sores at once?

A few days ago, I started getting these canker sores on my inner lower lip. I've tried rinsing with mouthwash which numbs them but they're still there. I've gotten them one at a time before, probably once every couple of months. However, now I have 4 or 5 in a line on my lower lip. It's painful, irritable and quite gross. I feel a couple more might appear on the top inner lip. This worries and saddens me..any guesses why a m influx of canker sores decided to befall me? :(