So sorry to hear about his prolonged suffering and I recommend that you speak with your doctor
about this concern. One of the most common conditions that can cause skin changes on the hands and feet and high temperatures is called hand-foot and mouth disease. It is caused by a virus and can last for a few days which can be quite stressful for parents. Often, the child will not want to eat or drink very much due to the pain of swallowing caused by the blisters inside of the mouth, which are often similar to the lesions on the hands (although they are not necessary for a diagnosis). There will sometimes be other skin changes on other body parts as well. As a parent, it is hard to know when there is something more serious that needs to be addressed, and so it is good to look for any changes that seem to signify that your son is getting worse. For example, if he stops walking, talking, or acting like his normal self, those would be signs that something more serious could be happening, and would be a good reason to speak with his doctor. Also, if he stops urinating or has any other symptoms that seem to get worse or persist. In any case, please ask your doctor about this question.