Unfortunately yes it was a bad idea using spray paint without adequate protection. But fortunately this is not likely to cause long term damage.
What you seem to be suffering from is an allergic reaction
to the paint. You need to make sure that you do not use paint any time soon and not at all without protection.
You need to start an antihistaminic drug as cetrizine
and make sure you drink plenty of water. Keep a very close watch on your breathing and if your chest tightness
increases or you develop wheeze(sounds while breathing) you need to be put on steroids
than and you need to go to a physician.
As of the rash on your face if it is still there you need to apply an ointment containing mild steroids as betnovate
but not for more than five days.
Wishing you a speedy recovery