Don't want to be disgusting but - how's the poop? Is it runny? Is it really dry? There should be a white part of it which is uric acid. How is that look? If it is dry and flaky he might need more water. It should look a little watery (slimy if you will) but overall solid.
When it comes to lizards there are two things to worry about
: are they eating? Are they pooping?
It's more involved than that but overall if he/she is active and eating regularly and pooping regularly and is not getting fat (check the armpit undersides, they shouldn't ahve anything that looks like a bubble under their skin - that's a sign of overfeeding) then you are fine.
I usually feed mine as much as she can eat in 15 minutes.