Is he OK with you being near it's cage? Can you handle him yet?
If he is OK with you being close, find a long bamboo skewer, put a treat (Bit of: banana, mango, papaya, half a grape) on the end of it and put it in front of your iguana's snout. He definitely (sp) will smell it. If that stresses him, then you have to wait, probably until he is fairly OK with you handling him.