Its hard to tell if he was sick before you got him or not, but as you can see there are a few things you were doing that needed to be corrected. The heat on his basking spot was very hot. 100 degrees it terribly hot for a panther especially a baby one. If i remember correctly i think they need a basking spot of around 80 degrees or so. that being said the basking spot is usually the hottest spot in the cage with lower temps throughout the cage that he can thermo-regulate with. He looked pretty dehydrated as well. Possibly a combination of high basking temps and also misting sessions being insufficient. Most people find that they need each misting session to be at least a couple of minutes. This gives the chameleon enough time to be stimulated in to drinking by the dropping of water, only then do they start drinking water. Another thing others have stated, calcium with D3 at every feeding is to much. They only need the D3 twice a month and at a young age i think this can quickly cause them to go down hill. Im not sure but from other cases it seems that to many supplements or d3 overdose also is hard on the kidneys, possibly speeding up dehydration in the little guys. So these things combined may have been a perfect storm for rapid downhill spiral to sickness and dehydration. On the other hand you said you have had him for only two weeks and i have seen people who have made similar mistakes with their new ones for longer and still had a chance to correct them and save their babies. Its hard to tell but on here you will find so many people and pages of information that will help you with success if you do choose to try again with another one. This is no way a definate answer and could be all wrong but just somethings to think about. I am sorry for your loss and really wish you the best of luck in the future!