It's been a long time since I've had a months old veiled, but we misted him about 3 times a day. That was Guido, who is now about 4 years old. We also mist our babies, 3 or 4 times a day. Always use warm water. Here is a nice article about baby cham care. The writer also recommends misting 3 times a day with warm water: http://www.chameleonnews.com/new/?page=article&id=115
you have to be very careful with youngins as well as adults.
usually as chameleons grow older they develop the sense to turn nose tip to the ground so that there "nostrils" are facing down and cannot be over run with water. Although this is a basic survival instinct, in captivity it is not garunteed your chameleon has this, especially when young!!!!
here are a couple guidelines to follow:
1. make sure there is plenty of room in the cage for you cham to escape the mist and stay dry.
2. start off with short mistings, focusing mosty on the foliage, this will allow him to interact with the water.
3. never give a misting session unsupervised, never supervised either for more than a couple minutes on a young cham.
4 after, when your cham has progressed when giving long infrequent showers, once again go back over this list.
5. small chams are highly susceptible to URI and if you leave them in a misted enclosure for two long, there is a good chance they will breath in that water, or vapor, and cause themselves hella health problems that will most likely lead to a gruesome death