Low temps can cause RIs. Symptoms of RI can include: wheezing, whistling, or popping sounds when breathing, gaping (open mouthed breathing), bubbles in the nostrils or mouth, and mucus discharge, which may be visible in or around the mouth and nostrils, or smeared on things in the enclosure, and possibly a few I'm not thinking of right now.

The best thing you can do for your snake if it gets an RI is to raise the temps a little above normal, and get it to a qualified herp vet. Get a culture done, so that you can be sure the antibiotics that are prescribed are effective against the particular infection that your snake has.

It is probably worthwhile to go ahead and raise the temps now, as a precautionary measure. It might make the difference between the snake being able to fight off a slight infection before you even notice it and a big vet bill, or it might not, but it won't hurt anything to have the temps a little higher than usual for a while.

I also highly recommend listening to this episode of ReptileRadio, which features Dr. Stahl, one of the world's best herp vets. He talks quite a lot about RIs, what causes them, how to treat them, etc. in this episode. It is kind of long, but totally worth the time:
http://www.blogtalkradio.com/reptile...ile-veterinary

Another danger of low temps is if the snake's stomach was full, the food won't digest properly, and that can cause a regurge. If your snake does regurge, I would skip one feeding, then for the next feeding feed a smaller amount than usual to make sure your snake gets back on track ok.