First off, your guy has really gorgeous stress colors, just don't piss him off that often!
Don't take my word for this. I don't have any ready pictures available on this and I'm going off memory. My Jacksons chameleon I seem to remember having a dark blue / black tip to his tongue. I THINK it may be normal, but a second opinion would likely be best.
On another note, I noticed your other thread about when you got this little guy. You mentioned in that thread that food runs rampant through his cage.
Have you developed a feeding cup system for him yet? The easiest way is to find a plastic cup that insects can't readily escape from, and attach it to the side of the cage, with a branch nearby he can get the insects from.
When you cup feed like this, it's much easier to ration what exactly he's eating, and how often.
If he's eating a couple of insects a day, it sounds like he's doing just fine. If he's really young, it might be more normal for him to eat heavier than that, but I can't tell exactly how old he is from your picture. He looks around 9-12 months?
Start worrying if he goes 3-5 days without eating.