OMG poor baby! Vet asap! after vet, you have to be very calm, quiet, and slow to Rehab. When chams are hurt they quit eating and may not have the strength to draw in big breaths to get moisture from the air, keep humidity up. Rehab is crucial until they are strong enough to eat and draw big breaths on their own. Hand feed favorites. Hornworms are high in calcium and water to hydrate and you can feed them easily from your hand. Dehydration is a killer to chams. One trick is to get a cotton ball soaking in a small bowl with bottled water and get a hand towel and dark cloth(dark tee shirt, nothing heavy). Have everything ready before you begin and get comfy to where you can set him on the towel on your chest and cover him with the dark cloth. When he is calm, reach over and pick up the cotton ball and wring it out a little then uncover his head. Squeeze some of the water, one to two drops at a time, onto his nose so it flows a bit over and on the sides of his mouth. Be patient this may take a while until he realizes it is water you are dripping on him, heance the towel, its for you. Once he knows what it is hopefully he may tilt his head upward and open his mouth enough so you can drip some water in and let him swallow it down and he will open up again for you. This technique saved my chameleons life and I have continued doing it about three days a week so it will not be so foreign to him if it is needed again. Also the quickest way to calm my chameleon down is to cover him with a dark cloth/sheet/blanket. To my cham, dark means sleep time and covering him makes him secure. Now I know every cham is different so you may have to find what works for yours. Also, when they molt, the feet are harder to get the shed off so they tend to rub them hard against everything in the cage. So check very thoroughly to see if there is something sharp or a branch that may have splintered. I see no reason why you cannot nurse him back to health. Remember, quite, patience, and calm will go a long way right now. If you need any further assist, feel free to message me.