I had this problem after spilling some water on my pocket (ok it was a water fight), although the phone was in a slip case the headphone socket was exposed and a small droplet of water got in shorting my headphone socket. Considering you have been running, sweat or even rain water could have made it's way in.
In the end the only way i could get the water out was to use a bike pump with the adapter for pumping up rugby and foot balls. It is small enough to fit into the jack. (It needs to be small enough to allow for the air you pump in to come back out the sides, my little adapter is about 1.5mm thick.) Use the pump then to force the water out although be careful because the adapter is very small so the air pressure is huge. I kept the screen lit during this so i could see if anything was deforming.
Note: Do not try and blow it out as there is too high a risk of you putting in more moisture from your breath.
Also I'm not sure if the air canisters are a good idea either, then tend to make things very cold.