Blue means is that when they are about to shed, that have a blue tint to them. RI means respiratory infection. It's a nasty "snake cold" of sorts. Their lungs fill with mucus and if untreated can lead to death. Symptoms are mucus from the nasal passages and constant yawning. If her temps have been low like what you said, you'll wanna use a stronger bulb. Bad thing about heat lamps is that they are humidity killers. You could make her a makeshift humid hide. Just get some moss and get it moist, but not dripping wet. She might go in there and that will help with a nice shed. Or mist the cage as needed when humidity gets too low.