Hopefully you used catalyst in the paint? If yes then you will need to respray the area. Does it have clear on it? There is no way to get the metallic run effect out yo just have to cover it with new paint, just let the old cure and if a catalyst was used it is cured, if no catalyst was used then you cannot do anything for several months! If you are careful you can sand the paint flat without breaking through the color coat, then depending on your skills with the paint gun it can be fogged in or repainted as needed to finish up. Good luck! Note that I have painted a lot of cars in the garage, did your temperature drop as you were painting? I have seen this result from low temps as the paint just isn't curing as expected then all of a sudden this is what can happen.