Can you take a temp reading at the bottom of his enclosure for us? That would give us an idea of temp range. It is possible that his enclosure is getting a bit warm.
You didn't answer all the questions, however, which makes it difficult to review your husbandry.
Also, what are your biggest concerns? Is it that he gets mad when you go near him? This is completely normal for a male veiled chameleon of that age. It is normal for them to get upset when you approach the cage, and then to hiss and gape and either lunge or flee when you open the door. It doesn't mean he's ill, and can actually mean that he is quite healthy and robust.
If your friend led you to believe this would be a friendly pet for you, then he was mistaken. It is very rare to find a friendly veiled chameleon. You may, however, be able to train him to become used to you. Some things that may help you accomplish that would be to:
always wear neutral colors (tan or dull green) when near him, and no distinct patterns on your shirt. Don't wear reds, pinks, blacks, purples.
approach his enclosure very slowly, wait until he has recognized you before opening the door.
respect his space. Don't reach into his cage unless absolutely necessary. Try to give him his food without reaching far into the cage. Do the cleaning later at night when he is completely asleep. This is pretty easy since they usually go to sleep in early evening.