im no expert but i did have a veiled die from a prolapse a couple years ago.if i were you i wouldnt try to force feed him after only being without food for 2 days.i think the stress of the surgery and of being force fed would be far more damaging than going a couple days without food.now if he wasnt drinking,then maybe id say something had to be done right away,as dehydration is one of the most damaging things for a chameleon.as long as hes hydrated,he should get around to eating when hes feeling a little better.you can usually tell by his eyes,tail,and crest,if hes dehydrated or starving.if his eyes or tail seem sunk in,then i would start to think about force feeding.if i was you,and as long as hes accepting liquids,i would try to get him to drink a little pedialite.its a liquid made for children who are dehydrated due to being sick.it is loaded with electrolights and sugars.the electrolights will keep him nice and hydrated and the sugars should give him some energy he is lacking from not eating.i was told by my vet,to give this to my chameleon when he got his prolapse and was not eating.it really seemed to help him and made him look a lot better but he eventually died from an infection.i think a reptile that goes off food can live quite a bit longer on pedialite than if he was drinking water alone.like i said,i am no expert and anyone who thinks this advise is crap,please comment.im only passing on what was suggested to me.i hate to say it but just in case your vet didnt tell you,chameleons do not usually recover from a prolapse or any illness for that matter.many times when a chameleon shows signs of illness,its often too late.they are very delicate animals and keeping them alive in captivity is hard enough when they are healthy forget about when they are sick.good luck and make sure to keep his cage sterile.i really believe that had mine not contracted the infection,he would have survived the surgery.he was really doing well for a while and began eating and gaining weight again.i think had i removed everything from his cage,sterilized everything,added porus free sterile perches and used a clean paper towel substrate,he would never had gotten the infection.but who knows,he could have gotten the infection at the vets office for all i know.anyway good luck and please keep us posted