Hi Breonna,
How old are they and for how long have they been coughing and sneezing?. I am not able to help much with your problem but this additional information may help the person that is knowledgeable enough to answer. I hope they are better soon!
Diedra
i don’t know much about agamid lizard species, but if she has a “strange dark spot” i’d be worried about infection or bruising. please get her to a vet as soon as one opens in the morning.