From the pictures his casque looks a little bit sunken in. Is the skin on each side of his casque somewhat round, flat, or sunken in? If its sunken in he's on the thin side. Is it possible to take him outside for some sun? that would suffice until you get the bulb, and it would even be better than the bulb if you could get him a few hours of natural sun light every day.
His eyes look a little sunken in to me, but it could just be because you are taking pictures of him. My veiled sucks his eyeballs right into his head when I try to take him out (a little exaggerated... ) How often do you mist? The sunken in eyes would indicate that he id dehydrated or ill. What color is the white part of his poops? Yellow, white, orange?
Does he always keep that pattern? That is a stress pattern.