How to spray paint face-down surfaces

Unfortunately, there is only one way to fix your boo-boo. Sand it back down to metal or enough to remove the drips. Next time, when using spray paint, remember several very thin coats are much better than one heavy coat. Always start the spray away from the object you want to paint. Move smoothly and fairly quickly across the area, then go past the end of the work before stopping the spray. Let the paint dry a bit before the next coat. Be patient, smooth and quick. Trying to put on too much at one time caused your drips. Good luck.

10 C or 50 F is not the optimal temp for aerosol spray painting, but should be OK. Most manufacturers recommend 60 F or above, but I wouldn't worry too much. The product will spray fine, the dry time may be a bit longer but it will dry fine. Try to get the painted pieces indoors to a warmer area as soon as they can be handled, and your paint will cure properly. Good Luck.