Chameleons can get over burns most of the time, especially with assistanct.. Eggs, however, can pose to be a problem. If you have an eggbound female, then you either have a dead chameleon or expensive veterinary visits and treatments. You have to understand that a female is a major responsibility and if you do not recognize the fact that Leo is in fact Leona, then it presents the chameleon with a whole different ball game of health issues that you may not be noticing because you believe that *he* is male.
Please post some pictures of the burn because we can't tell the severity just by explanation, no matter how detailed. If you are still unsure of the sex, then feel free to post more pictures of the base of the tail and the back legs. I am pretty sure we already covered it, but it's just in case you doubt the fact that she is female.