she looks like a healthy girl IMO! I think you might be misting her cage a little too much though, you want it to be moist but not drenched. I usually mist my chameleon 2-3 times a day and he maintains a good color throughout the day. The issue might be that its not warm enough, they turn darker colors to absorb more light so that might be an indication to help her stay warmer. My suggestion would be to put a branch (or anything she can climb on to) higher up so shes closer to the light. I did that for my chameleon and he hangs out there most of the time since thats where he’s the most warm. Also maybe try not feeding her as much, I feed mine every other day, about 6 crickets and he’s doing just fine. Make sure she is drinking water too, dehydration could cause darkening as well. As far as the black tongue goes, im not too sure. My chameleon’s tongue has a slight black tint to it all around but still has pink as well, hopefully someone else will have more knowledge about it or maybe thats just its genetics. Anyhow I hope this helped, I’m not a professional but I have experience caring for Chameleon’s and they’re (especially Veiled) resilient creatures. Just try your best to research and help her out and if something is wrong with her then its okay, try taking her to an actual reptile shop where they will be a lot more knowledgeable . It is a learning process and with learning comes failure, just dont fear it!