i beleive that is gular edema and i only have experience with it, with one of my chams and in her case, it is due to supplimenting, too much vitamins and my girls neck swells up just like that. i would do a quick search on the forum as i belive there can be other causes.
Question for the experts: is that beyond what would be expected for a gravid female?
Questions for the owner: Is it possible she has eggs? They do not need to be mated to produce eggs. Do you have a laying bin in her cage just in case? Regardless if she is currently carrying eggs or not, I think you should have one available to any female egg laying chameleon of that age.
possible eggs:
if she is carrying eggs, she needs a laying bin asap. Id cut out the multivitamins and any d3 at this point and only supplement plain phos free calcium. id also limit the amount of vit a ingredients in your gut load for the time being.
ive had experiences with gular edema with females. normally it is caught within the day it shows up and from that day they only get supplemented plain calcium till egg laying.
this is not to scare you and im not saying this is the case everytime. personally i have only seen gular edema that bad once and that female became egg bound. she was not given a proper laying site, proper supplements and feeders.
if she is not carrying eggs and it is from over supplementing. follow what is said about supplements and gut load stated above.
i am aware of a different treatment for this that i have not personally tried yet. if you get professional help that says your chameleon is not carrying eggs. pm me.
I'll also pop in with the fact that I've seen people here post that their females never displayed gravid colors when carrying infertile clutches, so it's possible and that possibility needs to be covered.
I do Have a laying bin in there for her, I keep her covered up all day just to give her privacy. I use a lot of information I get from here and trough the web. She has been cranky when I try to handle her. Exactly what is the right laying bin for her? I have a black pot (for plants) about maybe the size of a paint can empty with moist dirt is that OK? or should I put washed sand?
use 12-14" deep of sand and soil mix. make the mix moist so that you can dig a "tunnel" without it caving in. you can try this different ways. either just mix them together or use about 12 inches of sand on the bottom and then place a few inches of soil on top or you can also just try just sand alone.
This is not completely necessary but helpful imo. place a piece of fake foliage in the container and or a piece of drift wood.